fix loader trying to boot from active partition missing valid signature

Author: boeckmann

source/fdisk/Makefile

@@ -209,6 +209,7 @@ utf8tocp/utf8tocp.exe : utf8tocp/utf8tocp.obj
 # --- CLEANUP ---------------------------------------------------------------
 
 clean : .SYMBOLIC
+	rm -f bootnorm.c
 	rm -f *.obj
 	rm -f fdisk.lnk
 

source/fdisk/bootnorm.asm

@@ -16,6 +16,7 @@
 	RELOCATED_OFFSET equ 0x0600
 	PARTTBL_SIZE	 equ 64
 	PARTTBL_OFFSET	 equ 0x1be
+	MAGIC_OFFSET	 equ 0x1fe
 	CODE_SIZE	 equ 440
 
 org RELOCATED_OFFSET
@@ -67,7 +68,7 @@ chainload_bootsect:
 	call fatal			; does not return
 	db 'read error while reading drive', 0		
   .check_signature:
-	cmp word [signature], 0xaa55
+	cmp word [BOOTSECT_OFFSET+MAGIC_OFFSET], 0xaa55
 	je handoff_to_volume_bootrecord
 	call fatal				; does not return
 	db 'partition signature != 55AA', 0