diff --git a/platforms/nuttx/src/canbootloader/arch/stm32/board_identity.c b/platforms/nuttx/src/canbootloader/arch/stm32/board_identity.c
index a976b3a76a..a716ad2f12 100644
--- a/platforms/nuttx/src/canbootloader/arch/stm32/board_identity.c
+++ b/platforms/nuttx/src/canbootloader/arch/stm32/board_identity.c
@@ -48,7 +48,7 @@ int board_get_mfguid(mfguid_t mfgid)
 	uint32_t *chip_uuid = (uint32_t *) STM32_SYSMEM_UID;
 	uint32_t  *rv = (uint32_t *) &mfgid[0];
 
-	for (int i = 0; i < PX4_CPU_UUID_WORD32_LENGTH; i++) {
+	for (unsigned int i = 0; i < PX4_CPU_UUID_WORD32_LENGTH; i++) {
 		*rv++ = SWAP_UINT32(chip_uuid[(PX4_CPU_UUID_WORD32_LENGTH - 1) - i]);
 	}