diff --git a/ports/rp2/CMakeLists.txt b/ports/rp2/CMakeLists.txt
index f9a9efe62a..f5bd61c44e 100644
--- a/ports/rp2/CMakeLists.txt
+++ b/ports/rp2/CMakeLists.txt
@@ -54,6 +54,10 @@ if (MICROPY_PY_NETWORK_CYW43)
     set(PICO_CYW43_DRIVER_PATH ${MICROPY_DIR}/lib/cyw43-driver)
 endif()
 
+# Necessary submodules for all boards.
+string(CONCAT GIT_SUBMODULES "${GIT_SUBMODULES} " lib/mbedtls)
+string(CONCAT GIT_SUBMODULES "${GIT_SUBMODULES} " lib/tinyusb)
+
 # Include component cmake fragments
 include(${MICROPY_DIR}/py/py.cmake)
 include(${MICROPY_DIR}/extmod/extmod.cmake)
@@ -278,6 +282,11 @@ if (MICROPY_PY_NETWORK_NINAW10)
 endif()
 
 if (MICROPY_PY_NETWORK_WIZNET5K)
+    string(CONCAT GIT_SUBMODULES "${GIT_SUBMODULES} " lib/wiznet5k)
+    if((NOT (${ECHO_SUBMODULES})) AND NOT EXISTS ${MICROPY_DIR}/lib/wiznet5k/README.md)
+        message(FATAL_ERROR " wiznet5k not initialized.\n Run 'make BOARD=${MICROPY_BOARD} submodules'")
+    endif()
+
     target_compile_definitions(${MICROPY_TARGET} PRIVATE
         MICROPY_PY_NETWORK_WIZNET5K=1
         WIZCHIP_PREFIXED_EXPORTS=1
@@ -312,8 +321,6 @@ if (MICROPY_PY_NETWORK_WIZNET5K)
     list(APPEND MICROPY_SOURCE_EXTMOD
         ${MICROPY_DIR}/extmod/network_wiznet5k.c
     )
-
-    string(CONCAT GIT_SUBMODULES "${GIT_SUBMODULES} " lib/wiznet5k)
 endif()
 
 # Add qstr sources for extmod and usermod, in case they are modified by components above.
diff --git a/ports/rp2/Makefile b/ports/rp2/Makefile
index 6f8c621c2a..6d2fc00964 100644
--- a/ports/rp2/Makefile
+++ b/ports/rp2/Makefile
@@ -29,17 +29,10 @@ all:
 clean:
 	$(RM) -rf $(BUILD)
 
-GIT_SUBMODULES += lib/mbedtls lib/tinyusb
-
+# First ensure that pico-sdk is initialised, then use cmake to pick everything
+# else (including board-specific dependencies).
 submodules:
-	# lib/pico-sdk is required for the cmake build to function (as used for boards other than PICO below)
 	$(MAKE) -f ../../py/mkrules.mk GIT_SUBMODULES="lib/pico-sdk" submodules
-ifeq ($(BOARD),PICO)
-	# Run the standard submodules target with minimum required submodules above
-	$(MAKE) -f ../../py/mkrules.mk GIT_SUBMODULES="$(GIT_SUBMODULES)" submodules
-else
-	# Run submodules task through cmake interface to pick up any board specific dependencies.
-	GIT_SUBMODULES=$$(cmake -B $(BUILD)/submodules -DECHO_SUBMODULES=1 -DGIT_SUBMODULES="$(GIT_SUBMODULES)" ${CMAKE_ARGS} -S . 2>&1 | \
-	    grep 'GIT_SUBMODULES=' | cut -d= -f2); \
+	GIT_SUBMODULES=$$(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
-endif