diff --git a/plat/mediatek/mt8186/aarch64/platform_common.c b/plat/mediatek/mt8186/aarch64/platform_common.c
index 745e54750..9b9697f71 100644
--- a/plat/mediatek/mt8186/aarch64/platform_common.c
+++ b/plat/mediatek/mt8186/aarch64/platform_common.c
@@ -13,8 +13,6 @@ const mmap_region_t plat_mmap[] = {
 	/* for TF text, RO, RW */
 	MAP_REGION_FLAT(MTK_DEV_RNG0_BASE, MTK_DEV_RNG0_SIZE,
 			MT_DEVICE | MT_RW | MT_SECURE),
-	MAP_REGION_FLAT(MTK_DEV_RNG1_BASE, MTK_DEV_RNG1_SIZE,
-			MT_DEVICE | MT_RW | MT_SECURE),
 	MAP_REGION_FLAT(MTK_DEV_RNG2_BASE, MTK_DEV_RNG2_SIZE,
 			MT_DEVICE | MT_RW | MT_SECURE),
 	{ 0 }
diff --git a/plat/mediatek/mt8186/include/platform_def.h b/plat/mediatek/mt8186/include/platform_def.h
index bf26ead81..5a565562f 100644
--- a/plat/mediatek/mt8186/include/platform_def.h
+++ b/plat/mediatek/mt8186/include/platform_def.h
@@ -15,9 +15,7 @@
 
 /* Aggregate of all devices for MMU mapping */
 #define MTK_DEV_RNG0_BASE	IO_PHYS
-#define MTK_DEV_RNG0_SIZE	0x400000
-#define MTK_DEV_RNG1_BASE	(IO_PHYS + 0x1000000)
-#define MTK_DEV_RNG1_SIZE	0xa110000
+#define MTK_DEV_RNG0_SIZE	0x10000000
 #define MTK_DEV_RNG2_BASE	MT_GIC_BASE
 #define MTK_DEV_RNG2_SIZE	0x600000