MAC Address Problem

Help with booting MiniMyth

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s_g_robertson
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MAC Address Problem

Post by s_g_robertson » Thu Jun 14, 2007 10:39 pm

Hi all,

I know this isn't a question that is limited to minimyth, but that is what I am trying to get going and I didn't know where to ask.

I already have a minimyth frontend (EPIA M10000) that has been working successfully for quite a few months now. I bought another board, in theory exactly the same(it was secondhand).

My problem is that this new board sometimes starts up and reports a MAC address of all zeros, sometimes it does work and it has booted minimyth successfully and seemed to operate with no issues once it got going.

Has anyone come across this situation before?

Thanks
Stephen.

3d-lee
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Re: MAC Address Problem

Post by 3d-lee » Tue Jul 17, 2007 12:37 am

s_g_robertson wrote:My problem is that this new board sometimes starts up and reports a MAC address of all zeros, sometimes it does work and it has booted minimyth successfully and seemed to operate with no issues once it got going.
MAC addresses are typically stored in an EEPROM that sits off of the MAC. The MAC reads default register values in from this EEPROM when it comes out of reset and one of those values is the MAC address. If it works sometimes and not others then there is clearly something wrong with hardware.

It could have been a manufacturing or part defect and thus that way when it was new or it also could have been fine when it was new but was subsequently damaged by an electrostatic discharge (ESD). I doubt if it is a design or general parametric problem as this is the first I've ever heard of that type of problem with that board and there are a lot of M10000s in the wild.

s_g_robertson
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Post by s_g_robertson » Tue Jul 17, 2007 10:03 am

That was kind of what I was expecting. Is there anyway round that? Is there anyway to manually set a MAC address. Seems a shame to have to throw away a board just for that reason?


Or a thought I have just had while typing this could I use a PCI network card and disable the onboard LAN. I will investigate!

JoeHenley
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Post by JoeHenley » Tue Jul 17, 2007 2:40 pm

There are two possible ways to do this. There is a program called "mac changer" (search on google) which can manually set / change a mac address; also "ifconfig" can do the same thing, albeit with fewer options.

Good luck.

Joe Henley

3d-lee
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MAC address

Post by 3d-lee » Tue Jul 17, 2007 5:51 pm

If you are not trying to do a bootp/netboot then you should be able to manually set the MAC as was suggested. You'll need to do it before you try to DHCP.

Yes, disabling the onboard LAN and putting a NIC in the PCI slot should work too.

3d-lee
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missing MAC address

Post by 3d-lee » Tue Jul 17, 2007 8:06 pm

You know it dawned on me that if the MAC is occasionally all zeros then just manually setting the MAC might not fix things. That EEPROM stores other settings for the MAC chip too so if the MAC isn't being read then the other values are questionable too. That is, if the contents of the EEPROM aren't read by the MAC on occassion, it will almost certainly affect other aspects of the MAC too and not just the MAC address.

If you are insistent on using that board I would suggest disabling the onboard networking and use a PCI card if you have one handy. You can try just manually setting the MAC address but you might find the networking is still flakey.

pleeke
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Post by pleeke » Wed Jul 18, 2007 8:55 am

Just a thought, but I think there were problems with older bios' on M10000 boards (the OP said it was secondhand so might still have quite an old bios). I seem to remember having this sort of problem and needing to upgrade the bios, but it was a couple of years ago now!

3d-lee
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missing MAC address

Post by 3d-lee » Wed Jul 18, 2007 5:01 pm

It worth a shot and certainly can't hurt anything (unless the power goes out in the middle of the update:( It's hard to imagine that a BIOS update would fix this as the EEPROM is typically read automatically by the MAC when it's taken out of reset. (The MAC datasheets I've looked at are this way -- I have no specific knowledge of the M10000 MAC so it may be different.) Anything is possible though and it won't cost anything to try other than some time.

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