Changeset 216

Timestamp:

Nov 9, 2017, 11:25:45 PM (7 years ago)

Author:

Ben Rietbroek

Message:

Skip disks with a GPT (0xee) Identifier [v1.1.3-testing]

This is a quick-n-dirty hack to skip GPT disks.
GPT disks are not truly recognized and this hack has the semantics of
the disk having no partitions.

CAUTION:
This is a testbuild !
AirBoot uses the BIOS to access disks and a small coding error can trash
partition tables or other vital disk structures. You are advised to make
backups of TRACK0 and EBRs before using this testbuild. More info at:
​https://rousseaux.github.io/netlabs.air-boot/pdf/AirBoot-v1.1.2-manual.pdf

File:

• trunk/bootcode/regular/driveio.asm (modified) (1 diff)

trunk/bootcode/regular/driveio.asm ¶

@@ -308 +308 @@
 ;!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
         call    DriveIO_LoadSector
+
+        ; ----------------------------------------------------- [Check for GPT]
+        ; Check the 4 P-Table entries for a GPT identifier
+        ; If found, set CY and exit to indicate no partitions are found.
+        ; This prevents the disk from appearing in the menu with an 'unknown'
+        ; partition identifier.
+        cmp     byte ptr [si+01c2h], 0eeh   ; Check Entry #1
+        stc
+        jz      DIOLP_Success
+        cmp     byte ptr [si+01d2h], 0eeh   ; Check Entry #2
+        stc
+        jz      DIOLP_Success
+        cmp     byte ptr [si+01e2h], 0eeh   ; Check Entry #3
+        stc
+        jz      DIOLP_Success
+        cmp     byte ptr [si+01f2h], 0eeh   ; Check Entry #4
+        stc
+        jz      DIOLP_Success
 
         clc