diff --git a/client/src/ledger_app_clients/ethereum/client.py b/client/src/ledger_app_clients/ethereum/client.py
index 2ef41ff..6981f86 100644
--- a/client/src/ledger_app_clients/ethereum/client.py
+++ b/client/src/ledger_app_clients/ethereum/client.py
@@ -222,7 +222,7 @@ class EthAppClient:
             tmp = self._cmd_builder.set_external_plugin(plugin_name, contract_address, method_selelector, bytes())
 
             # skip APDU header & empty sig
-            sig = sign_data(Key.SET_PLUGIN, tmp[5:-1])
+            sig = sign_data(Key.CAL, tmp[5:])
         return self._send(self._cmd_builder.set_external_plugin(plugin_name, contract_address, method_selelector, sig))
 
     def personal_sign(self, path: str, msg: bytes):
diff --git a/src_features/setExternalPlugin/cmd_setExternalPlugin.c b/src_features/setExternalPlugin/cmd_setExternalPlugin.c
index 4a94356..49e827a 100644
--- a/src_features/setExternalPlugin/cmd_setExternalPlugin.c
+++ b/src_features/setExternalPlugin/cmd_setExternalPlugin.c
@@ -48,7 +48,9 @@ void handleSetExternalPlugin(uint8_t p1,
                          workBuffer + payload_size,
                          dataLength - payload_size)) {
 #ifndef HAVE_BYPASS_SIGNATURES
-        PRINTF("Invalid plugin signature %.*H\n", payload_size, workBuffer);
+        PRINTF("Invalid plugin signature %.*H\n",
+               dataLength - payload_size,
+               workBuffer + payload_size);
         THROW(0x6A80);
 #endif
     }