diff --git a/src/soc/intel/quark/memmap.c b/src/soc/intel/quark/memmap.c
index 53a1b24..d67856c 100644
--- a/src/soc/intel/quark/memmap.c
+++ b/src/soc/intel/quark/memmap.c
@@ -26,7 +26,8 @@
 	top_of_memory <<= 16;
 
 	/* Reserve 64 KiB for RMU firmware */
-	top_of_memory -= 0x10000;
+	if (top_of_memory)
+		top_of_memory -= 0x10000;
 
 	/* Return the top of memory */
 	return (void *)top_of_memory;