diff --git a/.gitignore b/.gitignore
index 65ca3013..40e58245 100644
--- a/.gitignore
+++ b/.gitignore
@@ -10,11 +10,3 @@
 /build/linux/arch/src
 /build/linux/arch/*.tar.gz
 /build/linux/arch/*.tar.xz
-
-# TODO this should be in devs global gitignore
-# it makes no sense to have it here
-*.log
-.DS_Store
-.vscode
-thumbs.db
-jsconfig.json
diff --git a/src/commands/getCurrentFirmware.js b/src/commands/getCurrentFirmware.js
index 773220ae..d4ae0c86 100644
--- a/src/commands/getCurrentFirmware.js
+++ b/src/commands/getCurrentFirmware.js
@@ -4,6 +4,7 @@ import { createCommand, Command } from 'helpers/ipc'
 import { fromPromise } from 'rxjs/observable/fromPromise'
 
 import getCurrentFirmware from 'helpers/devices/getCurrentFirmware'
+import type { FinalFirmware } from 'helpers/types'
 
 type Input = {
   deviceId: string | number,
@@ -11,7 +12,7 @@ type Input = {
   provider: number,
 }
 
-type Result = *
+type Result = FinalFirmware
 
 const cmd: Command<Input, Result> = createCommand('getCurrentFirmware', data =>
   fromPromise(getCurrentFirmware(data)),
diff --git a/src/commands/getDeviceInfo.js b/src/commands/getDeviceInfo.js
index 67c585fd..9cbbfae1 100644
--- a/src/commands/getDeviceInfo.js
+++ b/src/commands/getDeviceInfo.js
@@ -5,13 +5,15 @@ import { fromPromise } from 'rxjs/observable/fromPromise'
 import { withDevice } from 'helpers/deviceAccess'
 
 import getDeviceInfo from 'helpers/devices/getDeviceInfo'
-import type { DeviceInfo } from 'helpers/devices/getDeviceInfo'
+import type { DeviceInfo } from 'helpers/types'
 
 type Input = {
   devicePath: string,
 }
 
-const cmd: Command<Input, DeviceInfo> = createCommand('getDeviceInfo', ({ devicePath }) =>
+type Result = DeviceInfo
+
+const cmd: Command<Input, Result> = createCommand('getDeviceInfo', ({ devicePath }) =>
   fromPromise(withDevice(devicePath)(transport => getDeviceInfo(transport))),
 )
 
diff --git a/src/commands/getIsGenuine.js b/src/commands/getIsGenuine.js
index a1bb645d..e3e163b8 100644
--- a/src/commands/getIsGenuine.js
+++ b/src/commands/getIsGenuine.js
@@ -2,7 +2,7 @@
 
 import { createCommand, Command } from 'helpers/ipc'
 import { fromPromise } from 'rxjs/observable/fromPromise'
-import type { DeviceInfo } from 'helpers/devices/getDeviceInfo'
+import type { DeviceInfo } from 'helpers/types'
 
 import getIsGenuine from 'helpers/devices/getIsGenuine'
 import { withDevice } from 'helpers/deviceAccess'
diff --git a/src/commands/getLatestFirmwareForDevice.js b/src/commands/getLatestFirmwareForDevice.js
index d216d2eb..e88f6a50 100644
--- a/src/commands/getLatestFirmwareForDevice.js
+++ b/src/commands/getLatestFirmwareForDevice.js
@@ -2,11 +2,11 @@
 
 import { createCommand, Command } from 'helpers/ipc'
 import { fromPromise } from 'rxjs/observable/fromPromise'
-import type { DeviceInfo } from 'helpers/devices/getDeviceInfo'
+import type { DeviceInfo, OsuFirmware } from 'helpers/types'
 
 import getLatestFirmwareForDevice from '../helpers/devices/getLatestFirmwareForDevice'
 
-type Result = *
+type Result = ?(OsuFirmware & { shouldFlashMcu: boolean })
 
 const cmd: Command<DeviceInfo, Result> = createCommand('getLatestFirmwareForDevice', data =>
   fromPromise(getLatestFirmwareForDevice(data)),
diff --git a/src/commands/installApp.js b/src/commands/installApp.js
index 7fcc7db7..cd1a2e81 100644
--- a/src/commands/installApp.js
+++ b/src/commands/installApp.js
@@ -6,15 +6,15 @@ import { fromPromise } from 'rxjs/observable/fromPromise'
 import { withDevice } from 'helpers/deviceAccess'
 import installApp from 'helpers/apps/installApp'
 
-import type { LedgerScriptParams } from 'helpers/types'
+import type { ApplicationVersion } from 'helpers/types'
 
 type Input = {
-  app: LedgerScriptParams,
+  app: ApplicationVersion,
   devicePath: string,
   targetId: string | number,
 }
 
-type Result = *
+type Result = void
 
 const cmd: Command<Input, Result> = createCommand(
   'installApp',
diff --git a/src/commands/installMcu.js b/src/commands/installMcu.js
index 7d85e40b..660bd546 100644
--- a/src/commands/installMcu.js
+++ b/src/commands/installMcu.js
@@ -10,7 +10,7 @@ type Input = {
   devicePath: string,
 }
 
-type Result = *
+type Result = void
 
 const cmd: Command<Input, Result> = createCommand('installMcu', ({ devicePath }) =>
   fromPromise(withDevice(devicePath)(transport => installMcu(transport))),
diff --git a/src/commands/installOsuFirmware.js b/src/commands/installOsuFirmware.js
index f73a76d4..83b29a39 100644
--- a/src/commands/installOsuFirmware.js
+++ b/src/commands/installOsuFirmware.js
@@ -14,7 +14,7 @@ type Input = {
   firmware: Firmware,
 }
 
-type Result = *
+type Result = { success: boolean }
 
 const cmd: Command<Input, Result> = createCommand(
   'installOsuFirmware',
diff --git a/src/commands/listAppVersions.js b/src/commands/listAppVersions.js
index 494d7168..a802b2c6 100644
--- a/src/commands/listAppVersions.js
+++ b/src/commands/listAppVersions.js
@@ -2,11 +2,11 @@
 
 import { createCommand, Command } from 'helpers/ipc'
 import { fromPromise } from 'rxjs/observable/fromPromise'
-import type { DeviceInfo } from 'helpers/devices/getDeviceInfo'
+import type { DeviceInfo, ApplicationVersion } from 'helpers/types'
 
 import listAppVersions from 'helpers/apps/listAppVersions'
 
-type Result = *
+type Result = Array<ApplicationVersion>
 
 const cmd: Command<DeviceInfo, Result> = createCommand('listAppVersions', deviceInfo =>
   fromPromise(listAppVersions(deviceInfo)),
diff --git a/src/commands/listApps.js b/src/commands/listApps.js
index f049def3..13f78609 100644
--- a/src/commands/listApps.js
+++ b/src/commands/listApps.js
@@ -4,10 +4,11 @@ import { createCommand, Command } from 'helpers/ipc'
 import { fromPromise } from 'rxjs/observable/fromPromise'
 
 import listApps from 'helpers/apps/listApps'
+import type { Application } from 'helpers/types'
 
-type Input = {}
+type Input = void
 
-type Result = *
+type Result = Array<Application>
 
 const cmd: Command<Input, Result> = createCommand('listApps', () => fromPromise(listApps()))
 
diff --git a/src/commands/listCategories.js b/src/commands/listCategories.js
index 3632a47f..641b4ad8 100644
--- a/src/commands/listCategories.js
+++ b/src/commands/listCategories.js
@@ -4,10 +4,11 @@ import { createCommand, Command } from 'helpers/ipc'
 import { fromPromise } from 'rxjs/observable/fromPromise'
 
 import listCategories from 'helpers/apps/listCategories'
+import type { Category } from 'helpers/types'
 
-type Input = {}
+type Input = void
 
-type Result = *
+type Result = Array<Category>
 
 const cmd: Command<Input, Result> = createCommand('listCategories', () =>
   fromPromise(listCategories()),
diff --git a/src/commands/shouldFlashMcu.js b/src/commands/shouldFlashMcu.js
index 3bae3f04..f58c629c 100644
--- a/src/commands/shouldFlashMcu.js
+++ b/src/commands/shouldFlashMcu.js
@@ -2,9 +2,10 @@
 
 import { createCommand, Command } from 'helpers/ipc'
 import { fromPromise } from 'rxjs/observable/fromPromise'
-import type { DeviceInfo } from 'helpers/devices/getDeviceInfo'
 import shouldFlashMcu from 'helpers/devices/shouldFlashMcu'
 
+import type { DeviceInfo } from 'helpers/types'
+
 type Result = boolean
 
 const cmd: Command<DeviceInfo, Result> = createCommand('shouldFlashMcu', data =>
diff --git a/src/commands/uninstallApp.js b/src/commands/uninstallApp.js
index 59a61a3d..9b6df8a2 100644
--- a/src/commands/uninstallApp.js
+++ b/src/commands/uninstallApp.js
@@ -6,20 +6,20 @@ import { withDevice } from 'helpers/deviceAccess'
 
 import uninstallApp from 'helpers/apps/uninstallApp'
 
-import type { LedgerScriptParams } from 'helpers/types'
+import type { ApplicationVersion } from 'helpers/types'
 
 type Input = {
-  app: LedgerScriptParams,
+  app: ApplicationVersion,
   devicePath: string,
   targetId: string | number,
 }
 
-type Result = *
+type Result = void
 
 const cmd: Command<Input, Result> = createCommand(
   'uninstallApp',
-  ({ devicePath, targetId, ...rest }) =>
-    fromPromise(withDevice(devicePath)(transport => uninstallApp(transport, targetId, rest))),
+  ({ devicePath, targetId, ...app }) =>
+    fromPromise(withDevice(devicePath)(transport => uninstallApp(transport, targetId, app))),
 )
 
 export default cmd
diff --git a/src/components/GenuineCheck.js b/src/components/GenuineCheck.js
index b1012d4d..0b79cf69 100644
--- a/src/components/GenuineCheck.js
+++ b/src/components/GenuineCheck.js
@@ -9,7 +9,7 @@ import { delay, createCancelablePolling } from 'helpers/promise'
 
 import logger from 'logger'
 import type { T, Device } from 'types/common'
-import type { DeviceInfo } from 'helpers/devices/getDeviceInfo'
+import type { DeviceInfo } from 'helpers/types'
 
 import { GENUINE_TIMEOUT, DEVICE_INFOS_TIMEOUT, GENUINE_CACHE_DELAY } from 'config/constants'
 
diff --git a/src/components/ManagerPage/AppSearchBar.js b/src/components/ManagerPage/AppSearchBar.js
index cad33077..a9292f14 100644
--- a/src/components/ManagerPage/AppSearchBar.js
+++ b/src/components/ManagerPage/AppSearchBar.js
@@ -3,7 +3,7 @@
 import React, { PureComponent, Fragment } from 'react'
 import styled from 'styled-components'
 
-import type { LedgerScriptParams } from 'helpers/types'
+import type { ApplicationVersion } from 'helpers/types'
 
 import Box from 'components/base/Box'
 import Space from 'components/base/Space'
@@ -23,8 +23,8 @@ const CrossContainer = styled(Box).attrs({
 `
 
 type Props = {
-  list: Array<LedgerScriptParams>,
-  children: (list: Array<LedgerScriptParams>) => React$Node,
+  list: Array<ApplicationVersion>,
+  children: (list: Array<ApplicationVersion>) => React$Node,
 }
 
 type State = {
diff --git a/src/components/ManagerPage/AppsList.js b/src/components/ManagerPage/AppsList.js
index ae2644fe..e2f8bf1c 100644
--- a/src/components/ManagerPage/AppsList.js
+++ b/src/components/ManagerPage/AppsList.js
@@ -7,8 +7,7 @@ import { translate } from 'react-i18next'
 import { connect } from 'react-redux'
 import { compose } from 'redux'
 import type { Device, T } from 'types/common'
-import type { LedgerScriptParams } from 'helpers/types'
-import type { DeviceInfo } from 'helpers/devices/getDeviceInfo'
+import type { Application, ApplicationVersion, DeviceInfo } from 'helpers/types'
 import { developerModeSelector } from 'reducers/settings'
 
 import listApps from 'commands/listApps'
@@ -66,7 +65,7 @@ type Props = {
 type State = {
   status: Status,
   error: ?Error,
-  filteredAppVersionsList: LedgerScriptParams[],
+  filteredAppVersionsList: Array<ApplicationVersion>,
   appsLoaded: boolean,
   app: string,
   mode: Mode,
@@ -102,9 +101,14 @@ class AppsList extends PureComponent<Props, State> {
 
   filterAppVersions = (applicationsList, compatibleAppVersionsList) => {
     if (!this.props.isDevMode) {
-      return compatibleAppVersionsList.filter(
-        version => applicationsList.find(e => e.id === version.app).category !== 2,
-      )
+      return compatibleAppVersionsList.filter(version => {
+        const app = applicationsList.find(e => e.id === version.app)
+        if (app) {
+          return app.category !== 2
+        }
+
+        return false
+      })
     }
     return compatibleAppVersionsList
   }
@@ -112,7 +116,7 @@ class AppsList extends PureComponent<Props, State> {
   async fetchAppList() {
     try {
       const { deviceInfo } = this.props
-      const applicationsList = await listApps.send({}).toPromise()
+      const applicationsList: Array<Application> = await listApps.send().toPromise()
       const compatibleAppVersionsList = await listAppVersions.send(deviceInfo).toPromise()
       const filteredAppVersionsList = this.filterAppVersions(
         applicationsList,
@@ -131,7 +135,7 @@ class AppsList extends PureComponent<Props, State> {
     }
   }
 
-  handleInstallApp = (app: LedgerScriptParams) => async () => {
+  handleInstallApp = (app: ApplicationVersion) => async () => {
     this.setState({ status: 'busy', app: app.name, mode: 'installing' })
     try {
       const {
@@ -146,7 +150,7 @@ class AppsList extends PureComponent<Props, State> {
     }
   }
 
-  handleUninstallApp = (app: LedgerScriptParams) => async () => {
+  handleUninstallApp = (app: ApplicationVersion) => async () => {
     this.setState({ status: 'busy', app: app.name, mode: 'uninstalling' })
     try {
       const {
diff --git a/src/components/ManagerPage/Dashboard.js b/src/components/ManagerPage/Dashboard.js
index 2f04caff..3e726fab 100644
--- a/src/components/ManagerPage/Dashboard.js
+++ b/src/components/ManagerPage/Dashboard.js
@@ -4,7 +4,7 @@ import { translate } from 'react-i18next'
 import styled from 'styled-components'
 
 import type { T, Device } from 'types/common'
-import type { DeviceInfo } from 'helpers/devices/getDeviceInfo'
+import type { DeviceInfo } from 'helpers/types'
 
 import Box from 'components/base/Box'
 import Text from 'components/base/Text'
diff --git a/src/components/ManagerPage/FirmwareUpdate.js b/src/components/ManagerPage/FirmwareUpdate.js
index c289054c..dcaba901 100644
--- a/src/components/ManagerPage/FirmwareUpdate.js
+++ b/src/components/ManagerPage/FirmwareUpdate.js
@@ -9,7 +9,7 @@ import invariant from 'invariant'
 
 import type { Device, T } from 'types/common'
 
-import type { LedgerScriptParams } from 'helpers/types'
+import type { DeviceInfo, OsuFirmware } from 'helpers/types'
 import type { StepId } from 'components/modals/UpdateFirmware'
 
 import getLatestFirmwareForDevice from 'commands/getLatestFirmwareForDevice'
@@ -19,7 +19,6 @@ import installFinalFirmware from 'commands/installFinalFirmware'
 import installMcu from 'commands/installMcu'
 import DisclaimerModal from 'components/modals/UpdateFirmware/Disclaimer'
 import UpdateModal from 'components/modals/UpdateFirmware'
-import type { DeviceInfo } from 'helpers/devices/getDeviceInfo'
 
 import Tooltip from 'components/base/Tooltip'
 import Box, { Card } from 'components/base/Box'
@@ -43,7 +42,7 @@ type Props = {
 }
 
 type State = {
-  latestFirmware: ?LedgerScriptParams & ?{ shouldFlashMcu: boolean },
+  latestFirmware: ?OsuFirmware & ?{ shouldFlashMcu: boolean },
   modal: ModalStatus,
   stepId: ?StepId,
   shouldFlash: boolean,
diff --git a/src/components/ManagerPage/index.js b/src/components/ManagerPage/index.js
index 956d7c90..7c9631b2 100644
--- a/src/components/ManagerPage/index.js
+++ b/src/components/ManagerPage/index.js
@@ -6,7 +6,7 @@ import { openURL } from 'helpers/linking'
 import { urls } from 'config/urls'
 
 import type { Device } from 'types/common'
-import type { DeviceInfo } from 'helpers/devices/getDeviceInfo'
+import type { DeviceInfo } from 'helpers/types'
 
 import Dashboard from './Dashboard'
 
diff --git a/src/components/modals/UpdateFirmware/index.js b/src/components/modals/UpdateFirmware/index.js
index b6aac554..716db238 100644
--- a/src/components/modals/UpdateFirmware/index.js
+++ b/src/components/modals/UpdateFirmware/index.js
@@ -10,7 +10,7 @@ import SyncSkipUnderPriority from 'components/SyncSkipUnderPriority'
 
 import type { StepProps as DefaultStepProps, Step } from 'components/base/Stepper'
 import type { ModalStatus } from 'components/ManagerPage/FirmwareUpdate'
-import type { LedgerScriptParams } from 'helpers/types'
+import type { OsuFirmware } from 'helpers/types'
 
 import { FreezeDeviceChangeEvents } from '../../ManagerPage/HookDeviceChange'
 import StepFullFirmwareInstall from './steps/01-step-install-full-firmware'
@@ -56,7 +56,7 @@ const createSteps = ({ t, shouldFlashMcu }: { t: T, shouldFlashMcu: boolean }):
   return steps
 }
 
-export type Firmware = LedgerScriptParams & { shouldFlashMcu: boolean }
+export type Firmware = OsuFirmware & { shouldFlashMcu: boolean }
 
 export type StepProps = DefaultStepProps & {
   firmware: Firmware,
diff --git a/src/helpers/apps/installApp.js b/src/helpers/apps/installApp.js
index b5bb00f9..ce45f797 100644
--- a/src/helpers/apps/installApp.js
+++ b/src/helpers/apps/installApp.js
@@ -1,13 +1,12 @@
 // @flow
-import qs from 'qs'
 import type Transport from '@ledgerhq/hw-transport'
 
-import { BASE_SOCKET_URL } from 'config/constants'
 import { createDeviceSocket } from 'helpers/socket'
 
-import type { LedgerScriptParams } from 'helpers/types'
+import type { ApplicationVersion } from 'helpers/types'
 
 import { createCustomErrorClass } from 'helpers/errors'
+import { WS_INSTALL } from 'helpers/urls'
 
 const ManagerNotEnoughSpaceError = createCustomErrorClass('ManagerNotEnoughSpace')
 const ManagerDeviceLockedError = createCustomErrorClass('ManagerDeviceLocked')
@@ -37,8 +36,8 @@ function remapError(promise) {
 export default async function installApp(
   transport: Transport<*>,
   targetId: string | number,
-  { app }: { app: LedgerScriptParams },
-): Promise<*> {
+  { app }: { app: ApplicationVersion },
+): Promise<void> {
   const params = {
     targetId,
     perso: app.perso,
@@ -47,6 +46,7 @@ export default async function installApp(
     firmwareKey: app.firmware_key,
     hash: app.hash,
   }
-  const url = `${BASE_SOCKET_URL}/install?${qs.stringify(params)}`
-  return remapError(createDeviceSocket(transport, url).toPromise())
+
+  const url = WS_INSTALL(params)
+  await remapError(createDeviceSocket(transport, url).toPromise())
 }
diff --git a/src/helpers/apps/listAppVersions.js b/src/helpers/apps/listAppVersions.js
index b29ba127..bc48fc6a 100644
--- a/src/helpers/apps/listAppVersions.js
+++ b/src/helpers/apps/listAppVersions.js
@@ -1,14 +1,19 @@
 // @flow
 import network from 'api/network'
-import type { DeviceInfo } from 'helpers/devices/getDeviceInfo'
+import type { DeviceInfo, DeviceVersion, FinalFirmware, ApplicationVersion } from 'helpers/types'
 
 import { APPLICATIONS_BY_DEVICE } from 'helpers/urls'
 import getDeviceVersion from 'helpers/devices/getDeviceVersion'
 import getCurrentFirmware from 'helpers/devices/getCurrentFirmware'
 
-export default async (deviceInfo: DeviceInfo) => {
-  const deviceData = await getDeviceVersion(deviceInfo.targetId, deviceInfo.providerId)
-  const firmwareData = await getCurrentFirmware({
+type NetworkResponse = { data: { application_versions: Array<ApplicationVersion> } }
+
+export default async (deviceInfo: DeviceInfo): Promise<Array<ApplicationVersion>> => {
+  const deviceData: DeviceVersion = await getDeviceVersion(
+    deviceInfo.targetId,
+    deviceInfo.providerId,
+  )
+  const firmwareData: FinalFirmware = await getCurrentFirmware({
     deviceId: deviceData.id,
     fullVersion: deviceInfo.fullVersion,
     provider: deviceInfo.providerId,
@@ -20,6 +25,6 @@ export default async (deviceInfo: DeviceInfo) => {
   }
   const {
     data: { application_versions },
-  } = await network({ method: 'POST', url: APPLICATIONS_BY_DEVICE, data: params })
+  }: NetworkResponse = await network({ method: 'POST', url: APPLICATIONS_BY_DEVICE, data: params })
   return application_versions.length > 0 ? application_versions : []
 }
diff --git a/src/helpers/apps/listApps.js b/src/helpers/apps/listApps.js
index 372d5ad1..14fed369 100644
--- a/src/helpers/apps/listApps.js
+++ b/src/helpers/apps/listApps.js
@@ -2,8 +2,9 @@
 import network from 'api/network'
 
 import { GET_APPLICATIONS } from 'helpers/urls'
+import type { Application } from 'helpers/types'
 
-export default async () => {
+export default async (): Promise<Array<Application>> => {
   const { data } = await network({ method: 'GET', url: GET_APPLICATIONS })
   return data.length > 0 ? data : []
 }
diff --git a/src/helpers/apps/listCategories.js b/src/helpers/apps/listCategories.js
index 59836572..1c903b0a 100644
--- a/src/helpers/apps/listCategories.js
+++ b/src/helpers/apps/listCategories.js
@@ -2,8 +2,9 @@
 import network from 'api/network'
 
 import { GET_CATEGORIES } from 'helpers/urls'
+import type { Category } from 'helpers/types'
 
-export default async () => {
-  const { data } = await network({ method: 'GET', url: GET_CATEGORIES })
+export default async (): Promise<Array<Category>> => {
+  const { data }: { data: Array<Category> } = await network({ method: 'GET', url: GET_CATEGORIES })
   return data.length > 0 ? data : []
 }
diff --git a/src/helpers/apps/uninstallApp.js b/src/helpers/apps/uninstallApp.js
index 5bf3dd68..7ce6fef3 100644
--- a/src/helpers/apps/uninstallApp.js
+++ b/src/helpers/apps/uninstallApp.js
@@ -1,12 +1,11 @@
 // @flow
-import qs from 'qs'
 import type Transport from '@ledgerhq/hw-transport'
 
-import { BASE_SOCKET_URL } from 'config/constants'
 import { createDeviceSocket } from 'helpers/socket'
 
-import type { LedgerScriptParams } from 'helpers/types'
-import { createCustomErrorClass } from '../errors'
+import type { ApplicationVersion } from 'helpers/types'
+import { createCustomErrorClass } from 'helpers/errors'
+import { WS_INSTALL } from 'helpers/urls'
 
 const ManagerDeviceLockedError = createCustomErrorClass('ManagerDeviceLocked')
 const ManagerUninstallBTCDep = createCustomErrorClass('ManagerUninstallBTCDep')
@@ -30,8 +29,8 @@ function remapError(promise) {
 export default async function uninstallApp(
   transport: Transport<*>,
   targetId: string | number,
-  { app }: { app: LedgerScriptParams },
-): Promise<*> {
+  { app }: { app: ApplicationVersion },
+): Promise<void> {
   const params = {
     targetId,
     perso: app.perso,
@@ -40,6 +39,6 @@ export default async function uninstallApp(
     firmwareKey: app.delete_key,
     hash: app.hash,
   }
-  const url = `${BASE_SOCKET_URL}/install?${qs.stringify(params)}`
-  return remapError(createDeviceSocket(transport, url).toPromise())
+  const url = WS_INSTALL(params)
+  await remapError(createDeviceSocket(transport, url).toPromise())
 }
diff --git a/src/helpers/devices/getCurrentFirmware.js b/src/helpers/devices/getCurrentFirmware.js
index a98c01d5..c4ef5979 100644
--- a/src/helpers/devices/getCurrentFirmware.js
+++ b/src/helpers/devices/getCurrentFirmware.js
@@ -2,6 +2,7 @@
 import network from 'api/network'
 
 import { GET_CURRENT_FIRMWARE } from 'helpers/urls'
+import type { FinalFirmware } from 'helpers/types'
 
 type Input = {
   fullVersion: string,
@@ -9,8 +10,8 @@ type Input = {
   provider: number,
 }
 
-export default async (input: Input): Promise<*> => {
-  const { data } = await network({
+export default async (input: Input): Promise<FinalFirmware> => {
+  const { data }: { data: FinalFirmware } = await network({
     method: 'POST',
     url: GET_CURRENT_FIRMWARE,
     data: {
diff --git a/src/helpers/devices/getDeviceInfo.js b/src/helpers/devices/getDeviceInfo.js
index c3972e3d..24b6d7d1 100644
--- a/src/helpers/devices/getDeviceInfo.js
+++ b/src/helpers/devices/getDeviceInfo.js
@@ -5,17 +5,7 @@ import type Transport from '@ledgerhq/hw-transport'
 import getFirmwareInfo from 'helpers/firmware/getFirmwareInfo'
 import { FORCE_PROVIDER } from 'config/constants'
 
-export type DeviceInfo = {
-  targetId: string | number,
-  seVersion: string,
-  isBootloader: boolean,
-  flags: string,
-  mcuVersion: string,
-  isOSU: boolean,
-  providerName: string,
-  providerId: number,
-  fullVersion: string,
-}
+import type { DeviceInfo } from 'helpers/types'
 
 const PROVIDERS = {
   '': 1,
diff --git a/src/helpers/devices/getDeviceVersion.js b/src/helpers/devices/getDeviceVersion.js
index 698bc1fa..c681cfa9 100644
--- a/src/helpers/devices/getDeviceVersion.js
+++ b/src/helpers/devices/getDeviceVersion.js
@@ -2,8 +2,10 @@
 import { GET_DEVICE_VERSION } from 'helpers/urls'
 import network from 'api/network'
 
-export default async (targetId: string | number, provider: number): Promise<*> => {
-  const { data } = await network({
+import type { DeviceVersion } from 'helpers/types'
+
+export default async (targetId: string | number, provider: number): Promise<DeviceVersion> => {
+  const { data }: { data: DeviceVersion } = await network({
     method: 'POST',
     url: GET_DEVICE_VERSION,
     data: {
diff --git a/src/helpers/devices/getIsGenuine.js b/src/helpers/devices/getIsGenuine.js
index 9ea7c56d..3357042b 100644
--- a/src/helpers/devices/getIsGenuine.js
+++ b/src/helpers/devices/getIsGenuine.js
@@ -2,23 +2,29 @@
 import type Transport from '@ledgerhq/hw-transport'
 import { SKIP_GENUINE } from 'config/constants'
 import { WS_GENUINE } from 'helpers/urls'
-import type { DeviceInfo } from 'helpers/devices/getDeviceInfo'
+import type { DeviceInfo, FinalFirmware, DeviceVersion } from 'helpers/types'
 
 import { createDeviceSocket } from 'helpers/socket'
 import getCurrentFirmware from './getCurrentFirmware'
 import getDeviceVersion from './getDeviceVersion'
 
 export default async (transport: Transport<*>, deviceInfo: DeviceInfo): Promise<string> => {
-  const deviceVersion = await getDeviceVersion(deviceInfo.targetId, deviceInfo.providerId)
-  const firmware = await getCurrentFirmware({
+  const deviceVersion: DeviceVersion = await getDeviceVersion(
+    deviceInfo.targetId,
+    deviceInfo.providerId,
+  )
+
+  const firmware: FinalFirmware = await getCurrentFirmware({
     deviceId: deviceVersion.id,
     fullVersion: deviceInfo.fullVersion,
     provider: deviceInfo.providerId,
   })
+
   const params = {
     targetId: deviceInfo.targetId,
     perso: firmware.perso,
   }
+
   const url = WS_GENUINE(params)
   return SKIP_GENUINE
     ? new Promise(resolve => setTimeout(() => resolve('0000'), 1000))
diff --git a/src/helpers/devices/getLatestFirmwareForDevice.js b/src/helpers/devices/getLatestFirmwareForDevice.js
index 9bbf7296..80e14af8 100644
--- a/src/helpers/devices/getLatestFirmwareForDevice.js
+++ b/src/helpers/devices/getLatestFirmwareForDevice.js
@@ -1,7 +1,13 @@
 // @flow
 import network from 'api/network'
 import { GET_LATEST_FIRMWARE } from 'helpers/urls'
-import type { DeviceInfo } from 'helpers/devices/getDeviceInfo'
+import type {
+  DeviceInfo,
+  DeviceVersion,
+  FinalFirmware,
+  OsuFirmware,
+  McuVersion,
+} from 'helpers/types'
 
 import getFinalFirmwareById from 'helpers/firmware/getFinalFirmwareById'
 import getMcus from 'helpers/firmware/getMcus'
@@ -9,19 +15,31 @@ import getMcus from 'helpers/firmware/getMcus'
 import getCurrentFirmware from './getCurrentFirmware'
 import getDeviceVersion from './getDeviceVersion'
 
-export default async (deviceInfo: DeviceInfo) => {
+type NetworkResponse = {
+  data: {
+    result: string,
+    se_firmware_osu_version: OsuFirmware,
+  },
+}
+
+type Result = ?(OsuFirmware & { shouldFlashMcu: boolean })
+
+export default async (deviceInfo: DeviceInfo): Promise<Result> => {
   // Get device infos from targetId
-  const deviceVersion = await getDeviceVersion(deviceInfo.targetId, deviceInfo.providerId)
+  const deviceVersion: DeviceVersion = await getDeviceVersion(
+    deviceInfo.targetId,
+    deviceInfo.providerId,
+  )
 
   // Get firmware infos with firmware name and device version
-  const seFirmwareVersion = await getCurrentFirmware({
+  const seFirmwareVersion: FinalFirmware = await getCurrentFirmware({
     fullVersion: deviceInfo.fullVersion,
     deviceId: deviceVersion.id,
     provider: deviceInfo.providerId,
   })
 
   // Fetch next possible firmware
-  const { data } = await network({
+  const { data }: NetworkResponse = await network({
     method: 'POST',
     url: GET_LATEST_FIRMWARE,
     data: {
@@ -37,11 +55,13 @@ export default async (deviceInfo: DeviceInfo) => {
 
   const { se_firmware_osu_version } = data
   const { next_se_firmware_final_version } = se_firmware_osu_version
-  const seFirmwareFinalVersion = await getFinalFirmwareById(next_se_firmware_final_version)
+  const seFirmwareFinalVersion: FinalFirmware = await getFinalFirmwareById(
+    next_se_firmware_final_version,
+  )
 
-  const mcus = await getMcus()
+  const mcus: Array<McuVersion> = await getMcus()
 
-  const currentMcuVersionId = mcus
+  const currentMcuVersionId: Array<number> = mcus
     .filter(mcu => mcu.name === deviceInfo.mcuVersion)
     .map(mcu => mcu.id)
 
diff --git a/src/helpers/devices/shouldFlashMcu.js b/src/helpers/devices/shouldFlashMcu.js
index dba76d75..1ed0a768 100644
--- a/src/helpers/devices/shouldFlashMcu.js
+++ b/src/helpers/devices/shouldFlashMcu.js
@@ -1,7 +1,7 @@
 // @flow
 import network from 'api/network'
 import { GET_LATEST_FIRMWARE } from 'helpers/urls'
-import type { DeviceInfo } from 'helpers/devices/getDeviceInfo'
+import type { DeviceInfo } from 'helpers/types'
 
 import getFinalFirmwareById from 'helpers/firmware/getFinalFirmwareById'
 import getMcus from 'helpers/firmware/getMcus'
diff --git a/src/helpers/firmware/getFirmwareInfo.js b/src/helpers/firmware/getFirmwareInfo.js
index fc3033a1..b3c4a81c 100644
--- a/src/helpers/firmware/getFirmwareInfo.js
+++ b/src/helpers/firmware/getFirmwareInfo.js
@@ -1,6 +1,7 @@
 // @flow
 
 import type Transport from '@ledgerhq/hw-transport'
+import type { FirmwareInfo } from 'helpers/types'
 
 const APDUS = {
   GET_FIRMWARE: [0xe0, 0x01, 0x00, 0x00],
@@ -12,7 +13,7 @@ const APDUS = {
 /**
  * Retrieve targetId and firmware version from device
  */
-export default async function getFirmwareInfo(transport: Transport<*>) {
+export default async function getFirmwareInfo(transport: Transport<*>): Promise<FirmwareInfo> {
   const res = await transport.send(...APDUS.GET_FIRMWARE)
   const byteArray = [...res]
   const data = byteArray.slice(0, byteArray.length - 2)
diff --git a/src/helpers/firmware/getNextMCU.js b/src/helpers/firmware/getNextMCU.js
index 7565e379..3ab9337f 100644
--- a/src/helpers/firmware/getNextMCU.js
+++ b/src/helpers/firmware/getNextMCU.js
@@ -3,11 +3,14 @@ import network from 'api/network'
 
 import { GET_NEXT_MCU } from 'helpers/urls'
 import { createCustomErrorClass } from 'helpers/errors'
+import type { OsuFirmware } from 'helpers/types'
 
 const LatestMCUInstalledError = createCustomErrorClass('LatestMCUInstalledError')
 
+type NetworkResponse = { data: OsuFirmware | 'default' }
+
 export default async (bootloaderVersion: string): Promise<*> => {
-  const { data } = await network({
+  const { data }: NetworkResponse = await network({
     method: 'POST',
     url: GET_NEXT_MCU,
     data: {
diff --git a/src/helpers/firmware/installFinalFirmware.js b/src/helpers/firmware/installFinalFirmware.js
index a588e0e5..be13f6c1 100644
--- a/src/helpers/firmware/installFinalFirmware.js
+++ b/src/helpers/firmware/installFinalFirmware.js
@@ -1,6 +1,6 @@
 // @flow
 import type Transport from '@ledgerhq/hw-transport'
-import type { DeviceInfo } from 'helpers/devices/getDeviceInfo'
+import type { DeviceInfo, DeviceVersion, OsuFirmware, FinalFirmware } from 'helpers/types'
 
 import { WS_INSTALL } from 'helpers/urls'
 import { createDeviceSocket } from 'helpers/socket'
@@ -23,19 +23,19 @@ function remapSocketError(promise) {
   })
 }
 
-type Result = Promise<{ success: boolean, error?: string }>
+type Result = Promise<{ success: boolean }>
 
 export default async (transport: Transport<*>): Result => {
   try {
     const deviceInfo: DeviceInfo = await getDeviceInfo(transport)
-    const device = await getDeviceVersion(deviceInfo.targetId, deviceInfo.providerId)
-    const firmware = await getOsuFirmware({
+    const device: DeviceVersion = await getDeviceVersion(deviceInfo.targetId, deviceInfo.providerId)
+    const firmware: OsuFirmware = await getOsuFirmware({
       deviceId: device.id,
       version: deviceInfo.fullVersion,
       provider: deviceInfo.providerId,
     })
     const { next_se_firmware_final_version } = firmware
-    const nextFirmware = await getFinalFirmwareById(next_se_firmware_final_version)
+    const nextFirmware: FinalFirmware = await getFinalFirmwareById(next_se_firmware_final_version)
 
     const params = {
       targetId: deviceInfo.targetId,
diff --git a/src/helpers/firmware/installMcu.js b/src/helpers/firmware/installMcu.js
index aca208c8..d0ffb39e 100644
--- a/src/helpers/firmware/installMcu.js
+++ b/src/helpers/firmware/installMcu.js
@@ -7,6 +7,8 @@ import getNextMCU from 'helpers/firmware/getNextMCU'
 import getDeviceInfo from 'helpers/devices/getDeviceInfo'
 import { createCustomErrorClass } from 'helpers/errors'
 
+import type { DeviceInfo } from 'helpers/types'
+
 const ManagerDeviceLockedError = createCustomErrorClass('ManagerDeviceLocked')
 
 function remapSocketError(promise) {
@@ -20,16 +22,15 @@ function remapSocketError(promise) {
   })
 }
 
-type Result = Promise<*>
+type Result = Promise<void>
 
 export default async (transport: Transport<*>): Result => {
-  const deviceInfo = await getDeviceInfo(transport)
-  const { seVersion: version, targetId } = deviceInfo
+  const { seVersion: version, targetId }: DeviceInfo = await getDeviceInfo(transport)
   const nextVersion = await getNextMCU(version)
   const params = {
     targetId,
     version: nextVersion.name,
   }
   const url = WS_MCU(params)
-  return remapSocketError(createDeviceSocket(transport, url).toPromise())
+  await remapSocketError(createDeviceSocket(transport, url).toPromise())
 }
diff --git a/src/helpers/firmware/installOsuFirmware.js b/src/helpers/firmware/installOsuFirmware.js
index 603404e5..1121c340 100644
--- a/src/helpers/firmware/installOsuFirmware.js
+++ b/src/helpers/firmware/installOsuFirmware.js
@@ -27,7 +27,7 @@ function remapError(promise) {
   })
 }
 
-type Result = Promise<{ success: boolean, error?: any }>
+type Result = Promise<{ success: boolean }>
 
 export default async (
   transport: Transport<*>,
diff --git a/src/helpers/types.js b/src/helpers/types.js
index 56ac3f50..a9bea673 100644
--- a/src/helpers/types.js
+++ b/src/helpers/types.js
@@ -1,14 +1,134 @@
 // @flow
+type Id = number
+
 export type LedgerScriptParams = {
-  firmware?: string,
-  firmware_key?: string,
+  firmware: string,
+  firmwareKey: string,
   delete?: string,
-  delete_key?: string,
+  deleteKey?: string,
   targetId?: string | number,
+  hash: string,
+  perso: string,
+}
+
+export type DeviceInfo = {
+  targetId: string | number,
+  seVersion: string,
+  isBootloader: boolean,
+  flags: string,
+  mcuVersion: string,
+  isOSU: boolean,
+  providerName: string,
+  providerId: number,
+  fullVersion: string,
+}
+
+export type DeviceVersion = {
+  id: Id,
+  name: string,
+  display_name: string,
+  target_id: string,
+  description: string,
+  device: Id,
+  providers: Array<Id>,
+  mcu_versions: Array<Id>,
+  se_firmware_final_versions: Array<Id>,
+  osu_versions: Array<Id>,
+  application_versions: Array<Id>,
+  date_creation: string,
+  date_last_modified: string,
+}
+
+export type McuVersion = {
+  id: Id,
+  mcu: Id,
+  name: string,
+  description: ?string,
+  providers: Array<Id>,
+  from_bootloader_version: string,
+  device_versions: Array<Id>,
+  se_firmware_final_versions: Array<Id>,
+  date_creation: string,
+  date_last_modified: string,
+}
+
+export type FirmwareInfo = {
+  targetId: Id,
+  seVersion: string,
+  flags: string,
+  mcuVersion: string,
+}
+
+type BaseFirmware = {
+  id: Id,
+  name: string,
+  description: ?string,
+  display_name: ?string,
+  notes: ?string,
+  perso: string,
+  firmware: string,
+  firmware_key: string,
+  hash: string,
+  date_creation: string,
+  date_last_modified: string,
+  device_versions: Array<Id>,
+  providers: Array<Id>,
+}
+
+export type OsuFirmware = BaseFirmware & {
+  next_se_firmware_final_version: Id,
+  previous_se_firmware_final_version: Array<Id>,
+}
+
+export type FinalFirmware = BaseFirmware & {
+  version: string,
+  se_firmware: Id,
+  osu_versions: Array<OsuFirmware>,
+  mcu_versions: Array<Id>,
+  application_versions: Array<Id>,
+}
+
+export type ApplicationVersion = {
+  id: Id,
   name: string,
   version: string,
+  app: Id,
+  description: ?string,
+  display_name: string,
   icon: string,
-  app?: number,
-  hash?: string,
-  perso?: string,
+  picture: Id,
+  notes: ?string,
+  perso: string,
+  hash: string,
+  firmware: string,
+  firmware_key: string,
+  delete: string,
+  delete_key: string,
+  device_versions: Array<Id>,
+  se_firmware_final_versions: Array<Id>,
+  providers: Array<Id>,
+  date_creation: string,
+  date_last_modified: string,
+}
+
+export type Application = {
+  id: Id,
+  name: string,
+  description: ?string,
+  application_versions: Array<ApplicationVersion>,
+  providers: Array<Id>,
+  category: Id,
+  publisher: ?Id,
+  date_creation: string,
+  date_last_modified: string,
+}
+
+export type Category = {
+  id: Id,
+  name: string,
+  description: ?string,
+  providers: Array<Id>,
+  applications: Array<Id>,
+  date_creation: string,
+  date_last_modified: string,
 }