[ipxe-devel] FATAL: int13_eltorito: call with AX=4d00. Please report

Shao Miller sha0.miller at gmail.com
Wed Jan 2 09:41:54 GMT 2013


On 1/2/2013 02:30, Robin Smidsrød wrote:
> On 02.01.2013 01:23, Shao Miller wrote:
>> On 1/1/2013 15:18, Robin Smidsrød wrote:
>>> Anyone seen this before?
>>>
>>> https://dl.dropbox.com/u/354628/iPXE%20sanboot%20issue%202013-01-01.png
>
>> I'm pretty sure that this is from VirtualBox' BIOS.  Does it give the
>> same error message when you boot the DVD without any iPXE involvement?
>
> Booting the Windows 7 DVD inside vbox directly works as intended. No
> error messages appear.
>
>> ETDump can only be expected to give useful results if the CD/DVD was
>> actually booted.
>
> Very good point. I guess I'll have to put it inside an ISO file and boot
> _that_ to actually find the identifiers I'm looking for...

It can be handy to boot a minimal ISOLINUX .ISO with chain.c32 to chain 
either the HDD or a floppy; that way the El Torito emulation is started 
(for ETDump, ETTool, ElTorito.sys, etc.) but you needn't bother with 
more than a one-time mkisofs invocation.

Anyway, since it's working without iPXE, perhaps the iPXE INT 0x13 hook 
has a bug where the AH register is being incremented.  AH=0x4D means 
"Return Boot Catalog," but if it was an accidental increment, it 
might've been AH=0x4C, which is "Initiate Disk Emulation & Boot," which 
makes a whole lot of sense for the scenario you've described.

- Shao Miller


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