diff --git a/reactos/boot/freeldr/freeldr/arch/i386/hwdisk.c b/reactos/boot/freeldr/freeldr/arch/i386/hwdisk.c
index 52b775ead83..1eb5e84e950 100644
--- a/reactos/boot/freeldr/freeldr/arch/i386/hwdisk.c
+++ b/reactos/boot/freeldr/freeldr/arch/i386/hwdisk.c
@@ -150,8 +150,7 @@ static LONG DiskSeek(ULONG FileId, LARGE_INTEGER* Position, SEEKMODE SeekMode)
     if (Position->LowPart & (Context->SectorSize - 1))
         return EINVAL;
 
-    /* FIXME: take HighPart into account */
-    Context->SectorNumber = Position->LowPart / Context->SectorSize;
+    Context->SectorNumber = (ULONG)(Position->QuadPart / Context->SectorSize);
     return ESUCCESS;
 }