diff --git a/headers/private/kernel/platform/efi/protocol/block-io.h b/headers/private/kernel/platform/efi/protocol/block-io.h
index cf53e6b49b..6f1c52b8d2 100644
--- a/headers/private/kernel/platform/efi/protocol/block-io.h
+++ b/headers/private/kernel/platform/efi/protocol/block-io.h
@@ -26,10 +26,10 @@ struct efi_block_io_protocol {
                         bool ExtendedVerification) EFIAPI;
     efi_status (*ReadBlocks)(efi_block_io_protocol* self,
                              uint32_t MediaId, uint64_t LBA,
-                             uint64_t BufferSize, void* Buffer) EFIAPI;
+                             size_t BufferSize, void* Buffer) EFIAPI;
     efi_status (*WriteBlocks)(efi_block_io_protocol* self,
                               uint32_t MediaId, uint64_t LBA,
-                              uint64_t BufferSize, const void* Buffer) EFIAPI;
+                              size_t BufferSize, const void* Buffer) EFIAPI;
     efi_status (*FlushBlocks)(efi_block_io_protocol* self);
 
 
diff --git a/headers/private/kernel/platform/efi/types.h b/headers/private/kernel/platform/efi/types.h
index 0295e7fbc6..8aec5553d5 100644
--- a/headers/private/kernel/platform/efi/types.h
+++ b/headers/private/kernel/platform/efi/types.h
@@ -14,9 +14,14 @@
 #define EFIAPI
 #endif
 
+#if UINTPTR_MAX == 0xffffffff
+#define EFI_ERROR_MASK 0x80000000
+#elif UINTPTR_MAX == 0xffffffffffffffff
 #define EFI_ERROR_MASK 0x8000000000000000
+#endif
+
 #define EFI_ERR(x) (EFI_ERROR_MASK | x)
-#define EFI_ERROR(x) (((int64_t)x) < 0)
+#define EFI_ERROR(x) (((ssize_t)x) < 0)
 
 #define EFI_SUCCESS              0
 #define EFI_LOAD_ERROR           EFI_ERR(1)