thof
Posts: 18
Joined: Mon Mar 04, 2013 2:08 pm

Some CM3's not booting

Tue May 07, 2019 2:21 pm

Hi all,

I'm running into some issues and I have been scratching my head for some time, so I thought I would give you guys a go.

We are using the compute module 3 on a custom board with custom raspbian based OS. All works, but sometimes we run into 'faulthy' cm3's while trying to boot. We flash our OS image to the boards with Etcher, all is good and verification says all is fine. When we try to boot the module though it does not do anything. The activity LED just stays on and there is no screen. The strange thing is that this occurs maybe 1 in 20 compute modules. Others work just fine.

I thought it might be something with the flash chips having a different size, so the image and partitions have been resized to create additional unused space on the eMMC. Unfortunately this did not help.

The compute modules currently on my desk with these issues are all made in China.. not sure that would be the cause because others work just fine, but might be worthwhile mentioning.

The strange thing is, I can flash these modules with a clean raspbian and they work... just our custom image won't work on them. But when I use a different compute module I can flash our image and all works, just on these specific versions it does not do anything.

Any clues?

Thanks!

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piglet
Posts: 897
Joined: Sat Aug 27, 2011 1:16 pm

Re: Some CM3's not booting

Tue May 07, 2019 2:26 pm

Just a guess, but when seeing this sort of thing with other Pi's it was that the o/s being loaded didn't have the configuration for newer memory chips. As new chips get sourced the latest rasbian gets patched

Do the non-booting ones have different pop memory model to the working ones?


edit: viewtopic.php?p=437084 - old but what I was thinking of
There have been several hardware upgrades in the past which required a software upgrade. The transitions between different RAM PoP chips required an upgrade... this means your card has to have the latest NOOBS or Raspbian image...

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rpdom
Posts: 14460
Joined: Sun May 06, 2012 5:17 am
Location: Chelmsford, Essex, UK

Re: Some CM3's not booting

Tue May 07, 2019 2:42 pm

piglet wrote:
Tue May 07, 2019 2:26 pm
Do the non-booting ones have different pop memory model to the working ones?
Only the CM1 has PoP memory, but the point may be valid for other types of memory chip too.

gsh
Raspberry Pi Engineer & Forum Moderator
Raspberry Pi Engineer & Forum Moderator
Posts: 1416
Joined: Sat Sep 10, 2011 11:43 am

Re: Some CM3's not booting

Tue May 07, 2019 4:07 pm

Are you sure the CM3s are programmed with FAT32 formatted partition? Is this just a Raspbian image that has been modified and subsequently copied?

Can you plug the CM3 into a Pi, run rpiboot to convert into a mass storage then run (assuming it appears as /dev/sda)

sudo fdisk -l /dev/sda

Check if the first partition is FAT32 (not FAT16)

Gordon
--
Gordon Hollingworth PhD
Raspberry Pi - Director of Software Engineering

thof
Posts: 18
Joined: Mon Mar 04, 2013 2:08 pm

Re: Some CM3's not booting

Wed May 08, 2019 6:04 am

Thanks @gsh for the tip! It turned out to have a FAT16 boot partition... not sure where that came from I was under the impression it was a Raspbian Lite image which was stripped and modified for our purpose. Did old Raspbian images have FAT16 partitions?

Anyway problem solved, thanks! I will try to convert the boot partition to fat32 or maybe build a new image from the ground up!

fruitoftheloom
Posts: 19799
Joined: Tue Mar 25, 2014 12:40 pm
Location: Delightful Dorset

Re: Some CM3's not booting

Wed May 08, 2019 6:29 am

thof wrote:
Wed May 08, 2019 6:04 am
Thanks @gsh for the tip! It turned out to have a FAT16 boot partition... not sure where that came from I was under the impression it was a Raspbian Lite image which was stripped and modified for our purpose. Did old Raspbian images have FAT16 partitions?

Anyway problem solved, thanks! I will try to convert the boot partition to fat32 or maybe build a new image from the ground up!

Yes originally many years ago FAT12 & FAT16 were supported.
adieu

My other Computer is an Asus CS10 ChromeBit running Chrome Operating System.
HP Envy 4500 Wireless Printer supported by HPLIP software in Raspbian Buster.
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