Changeset 72 for trunk/bootcode/airboot.asm

Timestamp:

Apr 8, 2017, 12:26:07 AM (8 years ago)

Author:

Ben Rietbroek

Message:

Temporarily disable checksum verification for code [v1.1.1-testing]

In the development enviroment, we use VirtualBox with VMDK images.
To quickly test modifications, the AirBoot loader image is merged into
the VMDK image ouside of the VM. Because the 'airboot2.exe' installer
is not used, no checksum is embedded, so we temporarily disable
checksumming for the code section here.

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-v1.1.0-manual.pdf

File:

• trunk/bootcode/airboot.asm (modified) (1 diff)

trunk/bootcode/airboot.asm

@@ -807 +807 @@
                 loop    MBR_RealStart_CheckCodeLoop
 
-
+                ; Verify checksum
                 cmp     MBR_CheckCode, bx
-                je      MBR_RealStart_CheckSuccess
-
+                ;~ je      MBR_RealStart_CheckSuccess      ; CRC verified
+                jmp      MBR_RealStart_CheckSuccess     ; Ignore CRC
+
+                ; Oops, checksum mismatch -- halt the system
                 mov     si, offset TXT_ERROR_Attention
                 call    MBR_Teletype