Allow firmware update with invalid magic header after user confirmation

Software/PC_Application/LibreVNA-GUI/Device/LibreVNA/firmwareupdatedialog.cpp

@@ -2,6 +2,7 @@
 
 #include "ui_firmwareupdatedialog.h"
 #include "../../VNA_embedded/Application/Communication/PacketConstants.h"
+#include "CustomWidgets/informationbox.h"
 
 #include <QFileDialog>
 #include <QStyle>
@@ -60,8 +61,25 @@ void FirmwareUpdateDialog::on_bStart_clicked()
     char header[24];
     file->read(header, sizeof(header));
     if(strncmp(header, dev->getFirmwareMagicString().toStdString().c_str(), 4)) {
-        abortWithError("Invalid magic header constant");
+        // might be a firmware file for a wrong LibreVNA
-        return;
+        if(dev->getProtocolVersion() == Protocol::Version) {
+            // we are talking to a LibreVNA with the correct protocol, this is definitely the wrong firmware file
+            abortWithError("Invalid magic header constant");
+            return;
+        } else {
+            // we might be talking to the correct hardware but with the wrong protocol version (which might result
+            // in the magic string check falsely failing. Process after user confirmation
+            auto confirm = InformationBox::AskQuestion("Continue?", "The firmware magic header constant does not match the expected"
+                                                     " value for your LibreVNA. Either this is the wrong firmware file"
+                                                     " or the hardware ID of your LibreVNA was read incorrectly. This"
+                                                     " can happen if the LibreVNA uses a different protocol version than"
+                                                     " what it expected by the GUI. Do you want to continue with the firmware update?", true);
+            if(!confirm) {
+                abortWithError("Aborted by user");
+                return;
+            }
+        }
+
     }
     file->seek(0);
     state = State::ErasingFLASH;

Software/PC_Application/LibreVNA-GUI/Device/LibreVNA/librevnadriver.cpp

@@ -114,6 +114,7 @@ LibreVNADriver::LibreVNADriver()
     skipOwnPacketHandling = false;
     SApoints = 0;
     hardwareVersion = 0;
+    protocolVersion = 0;
     setSynchronization(Synchronization::Disabled, false);
 
     auto manual = new QAction("Manual Control");
@@ -589,6 +590,7 @@ void LibreVNADriver::handleReceivedPacket(const Protocol::PacketInfo &packet)
     switch(packet.type) {
     case Protocol::PacketType::DeviceInfo: {
         // Check protocol version
+        protocolVersion = packet.info.ProtocolVersion;
         if(packet.info.ProtocolVersion != Protocol::Version) {
             auto ret = InformationBox::AskQuestion("Warning",
                                         "The device reports a different protocol"
@@ -703,6 +705,11 @@ QString LibreVNADriver::hardwareVersionToString(uint8_t version)
     }
 }
 
+unsigned int LibreVNADriver::getProtocolVersion() const
+{
+    return protocolVersion;
+}
+
 unsigned int LibreVNADriver::getMaxAmplitudePoints() const
 {
     return limits_maxAmplitudePoints;

Software/PC_Application/LibreVNA-GUI/Device/LibreVNA/librevnadriver.h

@@ -184,6 +184,8 @@ public:
 
     QString getFirmwareMagicString();
 
+    unsigned int getProtocolVersion() const;
+
 signals:
     void receivedAnswer(const LibreVNADriver::TransmissionResult &result);
     void receivedPacket(const Protocol::PacketInfo& packet);
@@ -194,6 +196,7 @@ protected:
     QString hardwareVersionToString(uint8_t version);
 
     bool connected;
+    unsigned int protocolVersion;
     QString serial;
     Info info;
     uint8_t hardwareVersion;