[syslinux] Using of pxelinux configfiles for both BIOS and UEFI boot

[Leenders, Peter]

>>According to prior pcap reports, syslinux.efi searches for syslinux.cfg (too), while (l)pxelinux.0 will be searching for "default". >This means that using something *similar* to:
>> pxelinux.cfg/default:
>>  PATH bios
>>  CONFIG common-config.cfg ::bios
>>  # the bios modules should be located in the bios subdir
>>
>>and
>> pxelinux.cfg/syslinux.cfg
>>  PATH efi64
>>  CONFIG common-config.cfg ::efi64
>>  # the efi64 modules should be located in the efi64 subdir
>>
>>could / perhaps / might / work. It would also depend on how the path notation is expressed in "common-config.cfg", considering that >the CONFIG directive is changing the working directory.
>>
>>This might very well fail too, but perhaps this idea triggers some additional feedback from someone else.
>>
>>Regards,
>>Ady.
>
>Hello Ady,
>
>thank you for your response. I will check out this (hopefully) on Monday and give a short feedback to the list.
>
>I didn't notice this difference in the search order - but it can be. As far as I can see in my wireshark snapshots on the efi boot where is no search for a syslinux.cfg, but maybe on the bios boot, but I haven't one snapshot of this within reach.
>
>Peter

Hello Ady,

I checked this now by sniffing with wireshark but there is no search for pxelinux.cfg/syslinux.cfg in either bios or efi mode before searching for pxelinux.cfg/default. (using a renamed syslinux.efi in efi64 mode)

If I remove/rename the bootloader ldlinux.e64 the seachorder for efi is:
	Ldlinux.e64
	/ldlinux.e64
	/boot/isolinux/ldlinux.e64
	/isolinux/ldlinux.e64
	/boot/syslinux/ldlinux.e64
	/syslinux/ldlinux.e64
	/ldlinux.e64

If I remove/rename the configfile pxelinux.cfg/default the searchorder for efi is:

	pxelinux.cfg/uuid (or something similar)
	pxelinux.cfg/macaddress
	...
	pxelinux.cfg/(parts of macaddress)
	...
	pxelinux.cfg/default

and then the  boot fails with a "configuration file not found" error.

Peter