diff --git a/src/mainboard/starlabs/starbook/variants/mtl/romstage.c b/src/mainboard/starlabs/starbook/variants/mtl/romstage.c
index 7d9b9ae4fd..addcae5915 100644
--- a/src/mainboard/starlabs/starbook/variants/mtl/romstage.c
+++ b/src/mainboard/starlabs/starbook/variants/mtl/romstage.c
@@ -44,4 +44,5 @@ void mainboard_memory_init_params(FSPM_UPD *mupd)
 		mupd->FspmConfig.PcieRpEnableMask &= ~(1 << 8);
 
 	mupd->FspmConfig.PchHdaSubSystemIds = 0x70381e50;
+	mupd->FspmConfig.MmioSize = 0xb00;
 };