RP2040: Fix bug with bootloader getting stuck without SD card.

The bootloader code was overriding mbed main(), causing millis()
not to work, which broke timeouts.

src/ZuluSCSI_main.cpp

@@ -5,10 +5,20 @@
 
 extern "C" int bootloader_main(void);
 
+#ifdef USE_ARDUINO
+extern "C" void setup(void)
+{
+    bootloader_main();
+}
+extern "C" void loop(void)
+{
+}
+#else
 int main(void)
 {
     return bootloader_main();
 }
+#endif
 
 #else
 

src/build_bootloader.py

@@ -19,7 +19,7 @@ dep_objs = []
 for nodelist in env["PIOBUILDFILES"]:
     for node in nodelist:
         filename = str(node.rfile())
-        if 'ZuluSCSI_main.o' not in filename:
+        if 'ZuluSCSI_main' not in filename:
             dep_objs.append(node)
 # print("Bootloader dependencies: ", type(dep_objs), str([str(f.rfile()) for f in dep_objs]))