diff --git a/common/board_f.c b/common/board_f.c
index 5223453511..a5ead31ca7 100644
--- a/common/board_f.c
+++ b/common/board_f.c
@@ -309,7 +309,7 @@ __weak int mach_cpu_init(void)
 /* Get the top of usable RAM */
 __weak ulong board_get_usable_ram_top(ulong total_size)
 {
-#ifdef CONFIG_SYS_SDRAM_BASE
+#if defined(CONFIG_SYS_SDRAM_BASE) && CONFIG_SYS_SDRAM_BASE > 0
 	/*
 	 * Detect whether we have so much RAM that it goes past the end of our
 	 * 32-bit address space. If so, clip the usable RAM so it doesn't.