diff --git a/arch/arm64/kernel/efi.c b/arch/arm64/kernel/efi.c
index 9d4aa18f2a82..e8ca6eaedd02 100644
--- a/arch/arm64/kernel/efi.c
+++ b/arch/arm64/kernel/efi.c
@@ -122,12 +122,12 @@ static int __init uefi_init(void)
 
 	/* Show what we know for posterity */
 	c16 = early_memremap(efi_to_phys(efi.systab->fw_vendor),
-			     sizeof(vendor));
+			     sizeof(vendor) * sizeof(efi_char16_t));
 	if (c16) {
 		for (i = 0; i < (int) sizeof(vendor) - 1 && *c16; ++i)
 			vendor[i] = c16[i];
 		vendor[i] = '\0';
-		early_memunmap(c16, sizeof(vendor));
+		early_memunmap(c16, sizeof(vendor) * sizeof(efi_char16_t));
 	}
 
 	pr_info("EFI v%u.%.02u by %s\n",