On Mon, 2018-09-03 at 16:21:36 +0200, Steffen Grunewald wrote:
> On Mon, 2018-09-03 at 15:43:47 +0200, Thomas Lange wrote:
> > >>>>> On Mon, 3 Sep 2018 15:34:34 +0200, Steffen Grunewald 
> > >>>>> <steffen.grunew...@aei.mpg.de> said:
> > 
> >     >> I suggest you to retrieve the version of SYSLINUX 6.04; look here 
> > for more
> >     >> informations :
> >     >> 
> > https://groups.google.com/a/lbl.gov/forum/#!msg/warewulf/klTLgX-L4nw/IJZo3-jgAAAJ
> > 
> > Now I rembember that not the BIOS update fixed my Thinkpad problem,
> > but using a newer syslinux.efi from syslinux 6.04 was the proper fix.
> 
> Will try that next. (For whatever reason there was no update of syslinux
> in Debian for years... not even an backport. Stretch is growing old already.)

I owe you a report - a success report, that is.
Using the files from syslinux-{common,efi}_6.04~git (as recommended by Thomas,
already on July 11 - I must have missed that during my holidays), the boot delay
almost vanished. No issues booting the Dell machine, and I also succeeded with
an AMD Epyc one.
For the latter, I found that the UEFI mode results in 7 *more* available memory
pages than the LEGACY one (unless my counting algorithm is faulty).
Not too big a difference, and given that I had to flip seven switches to go UEFI
(boot mode, and 6 PCI-E OPROM modes), I'm still hesitant to enforce UEFI, but
at least now I know that UEFI-only hardware won't be a showstopper anymore.
(Got to think about adding a /boot/efi partition to all relevant 
disk_configs...)

Thanks for all your suggestions. 
Now back to the preparations for the new setup (delivery will be in November,
but I've got some hardware to test before)...

- Steffen

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