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

Michael Brown mbrown at fensystems.co.uk
Mon Jan 7 18:29:56 UTC 2013

On Monday 07 Jan 2013 17:33:09 Klaus Espenlaub wrote:
> We're listening... discussing internally how to resolve this without a
> BIOS panic. I agree with HPA that the proper way is checking first with
> function 4b01h if there is El Torito disk emulation in place, however
> panicing is too much.

Just returning with CF=1 and AX set to 0x01 ("invalid function or parameter") 
would be fine from iPXE's point of view.

> Regarding the complaints about trouble with returning to the BIOS to
> continue with other boot devices - this *is* troublesome, but since the
> code is open source there is lots of opportunity to improve things.
> Often it's clobbered memory contents outside the control of the BIOS.

Is iPXE clobbering anything?  We try to be careful about allocating memory 
properly (insofar as "properly" can be applied to the BIOS environment).


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