diff --git a/lib/bitcoin/hd-accounts-service.js b/lib/bitcoin/hd-accounts-service.js
index 63c3307..4de9787 100644
--- a/lib/bitcoin/hd-accounts-service.js
+++ b/lib/bitcoin/hd-accounts-service.js
@@ -144,10 +144,7 @@ class HDAccountsService {
     const externalPrm = hdaHelper.deriveAddresses(xpub, 0, _.range(gap.external), scheme)
     const internalPrm = hdaHelper.deriveAddresses(xpub, 1, _.range(gap.internal), scheme)
 
-    const external = await externalPrm
-    const internal = await internalPrm
-
-    const addresses = _.flatten([external, internal])
+    const addresses = _.flatten(await Promise.all([externalPrm, internalPrm]))
 
     return db.addAddressesToHDAccount(xpub, addresses)
   }
diff --git a/lib/wallet/wallet-service.js b/lib/wallet/wallet-service.js
index 8a09400..08cb7ad 100644
--- a/lib/wallet/wallet-service.js
+++ b/lib/wallet/wallet-service.js
@@ -365,10 +365,7 @@ class WalletService {
    */
   _mergeEntities(active, legacy, bip49, bip84, pubkeys) {
     // Put all xpub into active.xpubs
-    active.xpubs = active.xpubs
-      .concat(legacy.xpubs)
-      .concat(bip49.xpubs)
-      .concat(bip84.xpubs)
+    active.xpubs = active.xpubs.concat(legacy.xpubs, bip49.xpubs, bip84.xpubs)
 
     // Put addresses and pubkeys into active
     // but avoid duplicates
diff --git a/pushtx/status.js b/pushtx/status.js
index 918bfb0..ec60a0e 100644
--- a/pushtx/status.js
+++ b/pushtx/status.js
@@ -75,8 +75,7 @@ class Status {
     this.status.push.count = this.stats.count
 
     try {
-      await this._refreshNetworkInfo()
-      await this._refreshBlockchainInfo()
+      await Promise.all([this._refreshNetworkInfo(), this._refreshBlockchainInfo()])
     } catch (e) {
       Logger.error(e, 'PushTx : Status.getCurrent() : Error')
     } finally {
diff --git a/tracker/blockchain-processor.js b/tracker/blockchain-processor.js
index f0ee571..78e0d50 100644
--- a/tracker/blockchain-processor.js
+++ b/tracker/blockchain-processor.js
@@ -55,8 +55,7 @@ class BlockchainProcessor extends AbstractProcessor {
    * @returns {Promise}
    */
   async catchup() {
-    const highest = await db.getHighestBlock()
-    const info = await this.client.getblockchaininfo()
+    const [highest, info] = await Promise.all([db.getHighestBlock(), this.client.getblockchaininfo()])
     const daemonNbHeaders = info.headers
 
     // Consider that we are in IBD mode if Dojo is far in the past (> 13,000 blocks)
@@ -80,12 +79,11 @@ class BlockchainProcessor extends AbstractProcessor {
     try {
       Logger.info('Tracker : Tracker Startup (IBD mode)')
 
-      const info = await this.client.getblockchaininfo()
+      // Get highest block processed by the tracker
+      const [highest, info] = await Promise.all([db.getHighestBlock(), this.client.getblockchaininfo()])
       const daemonNbBlocks = info.blocks
       const daemonNbHeaders = info.headers
 
-      // Get highest block processed by the tracker
-      const highest = await db.getHighestBlock()
       const dbMaxHeight = highest.blockHeight
       let prevBlockId = highest.blockID
 
@@ -151,11 +149,10 @@ class BlockchainProcessor extends AbstractProcessor {
     try {
       Logger.info('Tracker : Tracker Startup (normal mode)')
 
-      const info = await this.client.getblockchaininfo()
+      // Get highest block processed by the tracker
+      const [highest, info] = await Promise.all([db.getHighestBlock(), this.client.getblockchaininfo()])
       const daemonNbBlocks = info.blocks
 
-      // Get highest block processed by the tracker
-      const highest = await db.getHighestBlock()
       if (highest == null) return null
       if (daemonNbBlocks == highest.blockHeight) return null
 
diff --git a/tracker/mempool-processor.js b/tracker/mempool-processor.js
index e3f7b00..17f8bf2 100644
--- a/tracker/mempool-processor.js
+++ b/tracker/mempool-processor.js
@@ -75,9 +75,11 @@ class MempoolProcessor extends AbstractProcessor {
     clearInterval(this.processMempoolId)
     //clearInterval(this.displayStatsId)
 
-    resolve(this.txSock.disconnect(keys.bitcoind.zmqTx).close())
-    resolve(this.pushTxSock.disconnect(keys.ports.notifpushtx).close())
-    resolve(this.orchestratorSock.disconnect(keys.ports.orchestrator).close())
+    this.txSock.disconnect(keys.bitcoind.zmqTx).close()
+    this.pushTxSock.disconnect(keys.ports.notifpushtx).close()
+    this.orchestratorSock.disconnect(keys.ports.orchestrator).close()
+
+    return Promise.resolve();
   }
 
   /**
@@ -255,11 +257,10 @@ class MempoolProcessor extends AbstractProcessor {
    */
   async _refreshActiveStatus() {
     // Get highest header in the blockchain
-    const info = await this.client.getblockchaininfo()
+    // Get highest block processed by the tracker
+    const [highestBlock, info] = await Promise.all([db.getHighestBlock(), this.client.getblockchaininfo()])
     const highestHeader = info.headers
 
-    // Get highest block processed by the tracker
-    const highestBlock = await db.getHighestBlock()
     if (highestBlock == null || highestBlock.blockHeight == 0) {
       this.isActive = false
       return