[ipxe-devel] 486 with a Realtek 8139

[Martin Habets]

Long ago Etherboot used to be i386 code.
Nowadays I think iPXE only runs on i586 or later,
e.g. arch/x86/prefix/unlzma.S has:
	.arch i586

>From memory there are a couple of places in the code where
iPXE uses assembler opcodes that don't exist in 486.
Your best bet is probably using the old Etherboot code base and
debug/patch that.

Martin

On Wed, May 05, 2021 at 01:37:46AM +0300, Nikolai Zhubr wrote:
> Hi all,
> 
> I'm having some trouble getting a Realtek 8139 card to boot successfully on
> a 486 box.
> 
> Long ago I made an rtl8139 rom using Etherboot project and flashed it into a
> number of EEPROM chips. I found them working fine with all systems I tried
> starting Pentium1. However, 486s had problems. Basically, pxelinux failed to
> run somehow, whereas if using Realtek's official ROM blob, pxelinux started
> successfully. Now I'm trying to workaround/fix/understand the issue.
> 
> My new idea was to chainload most current 8139 native image built from iPXE
> to see if it runs well on 486. Unfortunately, it does not:
> 
> ========= Screenshot ==========
> Loading 192.168.0.99:10ec8139.pxe ...(PXE)............................done
> PXE->EB: !PXE at 9F40:0000, entry point at 9F40:0680
> UNDI code segment 9F40:0AAD, data segment 9E40:1000 (633-640kB)
> UNDI device is PCI 00:0E.0, type Etherboot (workaround enabled)
> 640kB free base memory after PXE unload
> (nothing happens after that line, like completely hanging)
> ===============================
> 
> Supposedly there should not be any Pentium+ dependancies, right?
> Any other hints before I start digging through?
> 
> 
> Thank you,
> 
> Regards,
> Nikolai
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