diff --git a/ports/zephyr-cp/boards/rpi_pico_rp2040.overlay b/ports/zephyr-cp/boards/rpi_pico_rp2040.overlay
index 1cdd4ca2033..283debbe939 100644
--- a/ports/zephyr-cp/boards/rpi_pico_rp2040.overlay
+++ b/ports/zephyr-cp/boards/rpi_pico_rp2040.overlay
@@ -2,6 +2,13 @@
 	/delete-node/ partitions;
 
 	partitions {
+		/*
+		 * Without `ranges;` the addresses below stay flash-relative: the code partition resolves
+		 * to 0x100 instead of 0x10000100, so RP2_REQUIRES_SECOND_STAGE_BOOT is not selected (its
+		 * Kconfig tests for 0x10000100) and the image ships without a second-stage bootloader,
+		 * while the generated UF2 targets 0x00000100. Neither is loadable by the RP2040 boot ROM.
+		 */
+		ranges;
 		#address-cells = <1>;
 		#size-cells = <1>;