diff --git a/tests/big_firmware_tests.c b/tests/big_firmware_tests.c
index 4079adde03..0b0d200b74 100644
--- a/tests/big_firmware_tests.c
+++ b/tests/big_firmware_tests.c
@@ -16,7 +16,7 @@
 #include "utility.h"
 
 /* Choose a firmware size greater than the range of 32-bits unsigned. */
-#define BIG_FIRMWARE_SIZE ((uint64_t) 0x100000000)
+#define BIG_FIRMWARE_SIZE ((uint64_t) 0x100000000ULL)
 
 #define ROOT_KEY_BASE_NAME "testkeys/key_rsa8192"
 #define FIRMWARE_KEY_BASE_NAME "testkeys/key_rsa1024"
diff --git a/tests/big_kernel_tests.c b/tests/big_kernel_tests.c
index 81943ba662..b768f284a2 100644
--- a/tests/big_kernel_tests.c
+++ b/tests/big_kernel_tests.c
@@ -16,7 +16,7 @@
 #include "utility.h"
 
 /* Choose a kernel size greater than the range of 32-bits unsigned. */
-#define BIG_KERNEL_SIZE ((uint64_t) 0x100000000)
+#define BIG_KERNEL_SIZE ((uint64_t) 0x100000000ULL)
 
 #define FIRMWARE_KEY_BASE_NAME "testkeys/key_rsa2048"
 #define KERNEL_KEY_BASE_NAME "testkeys/key_rsa1024"