cleanups

Software/MainBoard/bootloader/main/CMakeLists.txt

@@ -0,0 +1 @@
+idf_component_register(SRCS "dummy.c" INCLUDE_DIRS ".")

Software/MainBoard/bootloader/main/dummy.c

@@ -0,0 +1,4 @@
+// This file intentionally left almost empty.
+// ESP-IDF expects at least one component; the bootloader build does not use this.
+
+void __unused_dummy_symbol(void) {}