Possible to remove eeprom?

[ferdster]

We have a custom board based on a BBB. It has the eeprom on it, but we'd like to get rid of it.

Initially, to bring up the board, we programmed the eeprom as a BBB. Now we want to remove it. I patched it with:

https://github.com/RobertCNelson/Bootloader-Builder/blob/master/patches/v2016.03/0002-NFM-Production-eeprom-assume-device-is-BeagleBone-Bl.patch

Now it boots with an empty eeprom. I thought the patch would be enough, but after removing the eeprom from the board, I get nothing at all on the console.

Something must be failing very early on in u-boot for it not to print anything.

I believe that the Linux kernel will not need the eeprom and it's only used in u-boot to pick which .dtb to load, correct?

Thanks for the help!

[Robert Nelson]

On Fri, Dec 16, 2016 at 6:29 PM, ferdster <ftja...@gmail.com> wrote:
> We have a custom board based on a BBB. It has the eeprom on it, but we'd
> like to get rid of it.
>
> Initially, to bring up the board, we programmed the eeprom as a BBB. Now we
> want to remove it. I patched it with:
> https://github.com/RobertCNelson/Bootloader-Builder/blob/master/patches/v2016.03/0002-NFM-Production-eeprom-assume-device-is-BeagleBone-Bl.patch
>
> Now it boots with an empty eeprom. I thought the patch would be enough, but
> after removing the eeprom from the board, I get nothing at all on the
> console.
>
> Something must be failing very early on in u-boot for it not to print
> anything.

Yeah, your going to have to dig deeper in u-boot, for beaglebone
clone's an eeprom on the i2c bus is expected..

You'll need to disable all those calls..

Regards,

--
Robert Nelson
https://rcn-ee.com/

[TJF]

Hi ferdster,

don't deal with any softtware!

Am Samstag, 17. Dezember 2016 01:29:35 UTC+1 schrieb ferdster:

but we'd like to get rid of it.

Just override (dd) the boot sector on the eeprom. The bootloader cannot find it and checks the next device in the regular sequence.

Regards

[ferdster]

Hallo TJF,

I think you are referring to the eMMC. I am talking about the small i2c eeprom that is used to identify the board.

Thanks.

[Charles Steinkuehler]

On 12/17/2016 12:12 PM, ferdster wrote:
> Hallo TJF,
>
> I think you are referring to the eMMC. I am talking about the small i2c eeprom
> that is used to identify the board.

Like Robert Nelson said, you're going to have to hack on U-Boot to
remove all the EEPROM calls.

...but unless you are *REALLY* worried about parts cost, I'd suggest
leaving it in the design. It makes a great place to store MAC
addresses, serial numbers, and any other board specific settings you
might need (DRAM flavor, production calibration values, or whatever).
Yes, you can store these in the eMMC or uSD, but that makes it much
more likely for these values to get overwritten or lost.

...and at least part of the EEPROM cost is covered by not having to
maintain a custom U-Boot branch for your board, and by simplified
software management later on if you ever ship similar but not quite
identical versions of your board. Imagine if all the BeagleBoard
variants didn't have an EEPROM and had to have a custom U-Boot and
flasher image for every version (and all the various ways folks in the
field would mess this up when upgrading!).

--
Charles Steinkuehler
cha...@steinkuehler.net

[lorriane...@yahoo.com]

--------------------------------------------
On Sat, 12/17/16, Charles Steinkuehler <cha...@steinkuehler.net> wrote:

Subject: Re: [beagleboard] Re: Possible to remove eeprom?
To: beagl...@googlegroups.com
Date: Saturday, December 17, 2016, 9:26 PM

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[cha...@sensemetrics.com]

Hello, 

I know this thread is a bit stale but I could use some assistance. So I built I customboard referenced about the beaglebone black wireless. I am also looking for help bypassing the eeprom check in u-boot. I was able to successfully build and bypass the eeprom check using your tutorial here. 

https://eewiki.net/display/linuxonarm/BeagleBone+Black

I would like to generate an SD card image with the jessie iot image found on beaglebone.org. Is it possible to use the same MLO and u-boot generated from the above tutorial? Is not, is the source for the u-boot used in the jessie iot image available?

Thanks in advance!

[William Hermans]

https://eewiki.net/display/linuxonarm/BeagleBone+Black#BeagleBoneBlack-Bootloader:U-Boot Link to the bootloader source there. Along with the whole build process.

Then I do believe what you're asking about removing the eeprom check is possible. Seems you have already done that, but I do remember some discussion about that being possible. However Robert would have to confirm that is possible on the Linux side of things. That, I'm not sure of.

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