Don't overwrite %dl with a (potentially) modified drive number if we

already handled the INT13 call.

src/arch/i386/interface/pcbios/int13.c

 		/* Set OF to indicate to wrapper not to chain this call */
 		ix86->flags |= OF;
 
-		break;
+		return;
 	}
 
 	/* Remap BIOS drive */