diff --git a/src/arch/x86/Kconfig b/src/arch/x86/Kconfig
index bb03db2..a488b55 100644
--- a/src/arch/x86/Kconfig
+++ b/src/arch/x86/Kconfig
@@ -147,9 +147,10 @@
 config CBFS_MCACHE_SIZE
 	hex
 	depends on !NO_CBFS_MCACHE
-	default 0x2000
+	default 0x4000
 	help
-	  Increase this value if you see CBFS mcache overflow warnings.
+	  Increase this value if you see CBFS mcache overflow warnings. Do NOT
+	  change this value for vboot RW updates!
 
 config PC80_SYSTEM
 	bool