isohdpfx: update to the new !GPT protocol

Update the check for !GPT to match the updated protocol (with length).

Signed-off-by: H. Peter Anvin <hpa@zytor.com>

diff --git a/mbr/isohdpfx.S b/mbr/isohdpfx.S
index 801115c..0bf807e 100644 (file)
--- a/mbr/isohdpfx.S
+++ b/mbr/isohdpfx.S
@@ -81,14 +81,16 @@ _start:
        jz      1f
        testb   $0x7f, (%si)            /* Invalid active flag field? */
        jnz     1f
+       cmpb    %cl, 4(%si)             /* Partition type zero == invalid? */
+       je      1f
        cmpl    $0x58504721, %eax       /* !GPT signature in EAX? */
        jne     2f
-       cmpb    $0xee, 4(%si)           /* EFI partition type? */
+       cmpb    $0xed, 4(%si)           /* EFI partition type? */
        jne     2f
        
        /* We have GPT partition information */
-       movl    (32+16)(%si), %ecx
-       movl    (36+16)(%si), %ebx
+       movl    (32+20)(%si), %ecx
+       movl    (36+20)(%si), %ebx
        jmp     1f
 
        /* We have non-GPT partition information */