Syslinux - Dec 2020 - pxelinux and UEFI laptops - broke everything which had worked with BIOS/pxelinux.0

Dear Colleagues,

For years I've been using pxelinux to provide an engineering menu to
workstations in the local network. I can run several versions of
memtest, hardware diagnostics tools, boot mfsBSD and other things.

Now I have several laptops with UEFI-only BIOSes, and I have found out
the hard way that my favorite tools do not work any more.

Of course I have replaced pxelinux.0 with syslinux.efi and provided
ldlinux.e64 and other things it wants.

A typical EFIx64/pxelinux.cfg/default entry looks like this:

label memtest2
  menu label ^8. Memtest86+ v4.20
  kernel memtest420

Now when I select it, I get

Loading memtest420... ok
Cannot relocate kernel. bailing out

And this entry:

label memtest3
 menu label ^7. Memtest-86 v4.3
 kernel memdisk
 append initrd=memtest86-floppy.img

produces the message "Loadig memtest86-floppy.img..." but then instant
reboot!

Is there I way I can fix all the above and continue enjoying my engineering
menu with the UEFI laptops?


-- 
Victor Sudakov,  VAS4-RIPE, VAS47-RIPN
2:5005/49 at fidonet http://vas.tomsk.ru/

A minimal search and reading would be enough to understand the problem.
> A typical EFIx64/pxelinux.cfg/default entry looks like this:
> 
> label memtest2
>   menu label ^8. Memtest86+ v4.20
>   kernel memtest420
 
Memtest86+ v4.20 is for BIOS (and/or CSM) only, not for UEFI.

> label memtest3
>  menu label ^7. Memtest-86 v4.3
>  kernel memdisk
>  append initrd=memtest86-floppy.img
 
 
memdisk (as of version 6.04-pre1) is for BIOS (and/or CSM) only, not 
for UEFI.

So, for UEFI boot, you need tools/kernels that are compatible with 
UEFI.

BTW, some EFI binaries are compatible with Secure Boot, and some are 
not - syslinux.efi 6.04-pre1 is/are in the latter group.

Regards,
Ady.