>

> On Fri, 2021-03-26 at 05:48 +0000, Einar Vading wrote:

> > > > Hi,

> > > >

> > > > On Thu, 2021-03-25 at 15:22 +0000, Einar Vading wrote:

> > > > > We have a Raspberry Pi 4 system set up using RAUC for updates and u-boot

> > > > > for

> > > > > booting. For some systems in the field we have the u-boot environment on

> > > > > the

> > > > > FAT boot partition and we mount that in fstab so that RAUC can access it

> > > > > with

> > > > > the fw_print/setenv commands.

> > > > >

> > > > > One issue we have seen is that the env-file gets corrupted every now and

> > > > > then.

> > > > > After corruption we can't RAUC update. The only solution we have to this

> > > > > problem now is to delete the corrupted env-file and reboot, then we can

> > > > > perform the upgrade.

> > > > >

> > > > > I have no idea how to track down whatever corrupts the file and I was

> > > > > wondering if anyone has any input.

> > > >

> > > > You could try placing the environment on a separate partition to avoid any

> > > > potential issues in the FAT implementation. Also, I think U-Boot has a way

> > > > to

> > > > support redundant environments.

> >

> > I have just done this for our newer systems. I moved the GPT partitions back

> > 4MB and placed two redundant environments between the GPT and the first GPT

> > partition.

> >

> > It is my understanding though that redundant environments are not supported

> > when storing the env on FAT?

>

> That's probably a question for the U-Boot mailing list. :)

>

> > > Exactly. This should also be documented in the U-Boot integration guideline

> > > for eMMC:

> > >

> > >

> > > https://rauc.readthedocs.io/en/latest/integration.html#example-setting-up-u-boot-environment-on-emmc-sd-card

> > >

> > > When writing to the FAT very short before hard rebooting, I could imagine

> > > this

> > > can lead to failures. Do you see the corruption only after updates, or also

> > > suddenly after n boots?

> >

> > Yes, this is something we have been able to test. If we cut the power

> > precisely when the env is written to FAT we can corrupt the entire boot

> > partition.

> > Super scary but this is not the problem we're seeing in the field. That

> > problem is more subtle.

>

> It should be possible to mount fat with the 'sync' option, but I'm not sure if

> that would help in this case. I'd recommend avoiding mounting FAT filesystems

> R/W if possible.

Maybe it could help with the problem I'm investigating. Don't think it would help with

the total corruption on powerloss when writing u-boot env, since that is in u-boot and

the fs is not "mounted" yet.

> > > How does the system report the corruption?

> >

> > fw_printenv and fw_setenv stops working and says that the env is corrupted.

> > That also means that RAUC update fails, that is usually when we notice it.

> >

> > Is there a way to watch a file and record any process that modifies it?

>

> There is blktrace, but you don't see the contents that way. It still may be

> enough detail to understand what's happening here.

Great, I'll check that out.

> Regards,

> Jan

Thanks for all the help.

Regards,

Einar