diff --git a/ports/esp32/Makefile b/ports/esp32/Makefile
index 8888180766b79..1ce4d97208da7 100644
--- a/ports/esp32/Makefile
+++ b/ports/esp32/Makefile
@@ -112,6 +112,6 @@ size-files:
 # output and passes the list of submodules to py/mkrules.mk which does the
 # `git submodule init` on each.
 submodules:
-	@GIT_SUBMODULES=$$(idf.py $(IDFPY_FLAGS) -B $(BUILD)/submodules -D ECHO_SUBMODULES=1 build 2>&1 | \
+	@GIT_SUBMODULES=$$(IDF_COMPONENT_MANAGER=0 idf.py $(IDFPY_FLAGS) -B $(BUILD)/submodules -D ECHO_SUBMODULES=1 build 2>&1 | \
 	                  grep '^GIT_SUBMODULES=' | cut -d= -f2); \
-	$(MAKE) -f ../../py/mkrules.mk GIT_SUBMODULES="$${GIT_SUBMODULES}" submodules
+	$(MAKE) -f ../../py/mkrules.mk GIT_SUBMODULES="$${GIT_SUBMODULES}" GIT_SUBMODULES_FAIL_IF_EMPTY=1 submodules
diff --git a/ports/esp32/esp32_common.cmake b/ports/esp32/esp32_common.cmake
index b6bfcdacc3cb4..e03d2ff11aada 100644
--- a/ports/esp32/esp32_common.cmake
+++ b/ports/esp32/esp32_common.cmake
@@ -60,7 +60,7 @@ list(APPEND MICROPY_SOURCE_DRIVERS
 )
 
 string(CONCAT GIT_SUBMODULES "${GIT_SUBMODULES} " lib/tinyusb)
-if(MICROPY_PY_TINYUSB)
+if(MICROPY_PY_TINYUSB AND NOT ECHO_SUBMODULES)
     set(TINYUSB_SRC "${MICROPY_DIR}/lib/tinyusb/src")
     string(TOUPPER OPT_MCU_${IDF_TARGET} tusb_mcu)
 
diff --git a/ports/rp2/Makefile b/ports/rp2/Makefile
index afa21cc7a4383..200899d338e6a 100644
--- a/ports/rp2/Makefile
+++ b/ports/rp2/Makefile
@@ -76,4 +76,4 @@ submodules:
 	$(MAKE) -f ../../py/mkrules.mk GIT_SUBMODULES="lib/pico-sdk" submodules
 	@GIT_SUBMODULES=$$(cmake -B $(BUILD)/submodules -DECHO_SUBMODULES=1 ${CMAKE_ARGS} -S . 2>&1 | \
 	                  grep '^GIT_SUBMODULES=' | cut -d= -f2); \
-	$(MAKE) -f ../../py/mkrules.mk GIT_SUBMODULES="$${GIT_SUBMODULES}" submodules
+	$(MAKE) -f ../../py/mkrules.mk GIT_SUBMODULES="$${GIT_SUBMODULES}" GIT_SUBMODULES_FAIL_IF_EMPTY=1 submodules
diff --git a/py/mkrules.mk b/py/mkrules.mk
index 875ddee8523b8..90e87541ac55e 100644
--- a/py/mkrules.mk
+++ b/py/mkrules.mk
@@ -257,6 +257,13 @@ ifneq ($(GIT_SUBMODULES),)
 	# Fallback to standard submodule update if blobless isn't available (earlier than 2.36.0)
 	$(Q)cd $(TOP) && git submodule update --init --filter=blob:none $(GIT_SUBMODULES) || \
 	  git submodule update --init $(GIT_SUBMODULES)
+else
+ifeq ($(GIT_SUBMODULES_FAIL_IF_EMPTY),1)
+	# If you see this error, it may mean the internal step run by the port's build
+	# system to find git submodules has failed. Double-check dependencies are set correctly.
+	$(ECHO) "Internal build error: The submodule list should not be empty."
+	exit 1
+endif
 endif
 .PHONY: submodules