[vortex] 3c905c ROM enable/disable

[sacrificial-spam-address@horizon.com]

>From Bogdan.Costescu@IWR.Uni-Heidelberg.De Wed Nov 08 14:21:55 2000
Delivered-To: colin@horizon.com
Delivered-To: sacrificial-spam-address@horizon.com
Date: Wed, 8 Nov 2000 15:21:45 +0100 (CET)
From: Bogdan Costescu <Bogdan.Costescu@IWR.Uni-Heidelberg.De>
To: sacrificial-spam-address@horizon.com
cc: vortex@scyld.com
Subject: Re: [vortex] 3c905c ROM enable/disable
In-Reply-To: <20001108043901.7109.qmail@science.horizon.com>
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On 8 Nov 2000 sacrificial-spam-address@horizon.com wrote:

>> I recently got frustrated enough with the fact that the network BIOS in
>> my 3c905c was delaying the boot sequence all the time to make a DOS boot
>> floppy and run 3com's 3c90xcfg.exe. 

Bogdan Costescu replied:
> I've never seen this (making of a boot floppy from EEPROM) and I have a
> lot of 905C cards. However, the main question is: do you want to boot off
> the card's EEPROM ? The computers that I bought during the last 6 months
> have an option in BIOS that allow to boot from network or not, just like
> booting off the floppy, HD or CDROM. I just disable network booting (or
> put it lower than floppy/HD) and never bother about EEPROM content.

> However, if you need to boot off EEPROM, you'd better rewrite the EEPROM
> content; I think that vortex-diag is capable of doing this and the image
> can be created with Etherboot.

Um, perhaps I was unclear.  There are *two* EEPROMs on the card.
One is a 64K "boot ROM".  It starts with the "55aa" BIOS signature
and contains x86 code.

The other, which vortex-diag refers to as "the" EEPROM, is a small
serial EEPROM with 128 bytes of config data, like the MAC address,
transciever mode (10/100 half/full duplex), and so on.

The boot ROM I don't want or need; I just ended up getting it by
looking for a good cheap network card and finding a 3c905 available.

3com supply a DOS utility to adjust (some of) "the" EEPROM settings.
One of the settings disables the boot ROM, so the BIOS doesn't see it.
This speeds up booting, because it doesn't display a message and wait
for a timeout.  I hadn't used it because I don't boot DOS, and Mr. "Wonderful"
Becker's vortex-diag.c doesn't let you fiddle that particular setting

I was recompiling kernels a lot and got annoyed at the delay.  So I put
DOS on a floppy and added the 3com utility.  Then I backed up the boot
ROM (just to be safe) from Linux, and adjusted the setting.  The boot
ROM went away.  (As opposed to, say, changing the boot signature.)

I thought the analysis might be worth sharing.