diff --git a/reactos/boot/freeldr/freeldr/include/arch/pc/machpc.h b/reactos/boot/freeldr/freeldr/include/arch/pc/machpc.h
index 0dddeb0fef9..0ce2dbd94d3 100644
--- a/reactos/boot/freeldr/freeldr/include/arch/pc/machpc.h
+++ b/reactos/boot/freeldr/freeldr/include/arch/pc/machpc.h
@@ -49,7 +49,7 @@ VOID PcPrepareForReactOS(IN BOOLEAN Setup);
 
 PFREELDR_MEMORY_DESCRIPTOR PcMemGetMemoryMap(ULONG *MemoryMapSize);
 
-BOOLEAN PcDiskGetBootPath(char *BootPath, unsigned Size);
+BOOLEAN PcDiskGetBootPath(OUT PCHAR BootPath, IN ULONG Size);
 BOOLEAN PcDiskReadLogicalSectors(UCHAR DriveNumber, ULONGLONG SectorNumber, ULONG SectorCount, PVOID Buffer);
 BOOLEAN PcDiskGetPartitionEntry(UCHAR DriveNumber, ULONG PartitionNumber, PPARTITION_TABLE_ENTRY PartitionTableEntry);
 BOOLEAN PcDiskGetDriveGeometry(UCHAR DriveNumber, PGEOMETRY DriveGeometry);