diff --git a/plugins/keepkey/keepkey.py b/plugins/keepkey/keepkey.py
index 0355e50a1..3ec6d105d 100644
--- a/plugins/keepkey/keepkey.py
+++ b/plugins/keepkey/keepkey.py
@@ -327,7 +327,7 @@ class KeepKeyPlugin(HW_PluginBase):
             txinputtype.prev_hash = prev_hash
             txinputtype.prev_index = prev_index
 
-            if 'scriptSig' in txin:
+            if txin.get('scriptSig') is not None:
                 script_sig = bfh(txin['scriptSig'])
                 txinputtype.script_sig = script_sig
 
diff --git a/plugins/trezor/trezor.py b/plugins/trezor/trezor.py
index f0dff3058..1de3e8262 100644
--- a/plugins/trezor/trezor.py
+++ b/plugins/trezor/trezor.py
@@ -379,7 +379,7 @@ class TrezorPlugin(HW_PluginBase):
             txinputtype.prev_hash = prev_hash
             txinputtype.prev_index = prev_index
 
-            if 'scriptSig' in txin:
+            if txin.get('scriptSig') is not None:
                 script_sig = bfh(txin['scriptSig'])
                 txinputtype.script_sig = script_sig