WD MyCloud Gen2 (Glacier, Armada 375)

Man Wrote:
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> I wonder if someone can help me. I'm about to go
> on an extended vacation and wanted a little nas
> with plex running with me, so I thought of
> bringing this thing with me. I have had the wdmcg2
> which I haven't touched since 2016. It's been
> running Debian jessie with Fox' 3.10 kernel, just
> a little samba server basically.
> I thought I might as well upgrade it to Trixie,
> and the original kernel worked fine up until
> Buster or something. After that I couldn't log in
> via SSH, so I put on John's 4.12.0 kernel and the
> it started working again and I managed to upgrade
> to Debian.
>
> Now, I saw that when upgrading the kernel using
> using Gparted from a live distro on my pc that
> sda2 and sd3 had switched places. So that the
> physical second partiton with the rootfs is
> actually sda3 and the third partiton is sda2
> (while sda1 is linux-swap). That bugged me, so
> after moving things around with gparted I got
> rootfs=sda3 into the actual third partiton and the
> sda2 to the second partition. Now it won't boot
> from either the second or third partiton?
I know where the fault is.
When I first installed Debian ages ago I blindly followed instructions from fox.exe. And ended up with sda3 as the 2nd physical partition and couldn’t understand why he would do that.

Well, it seems even though the bootloader is hard coded to boot from sda3, there is a limit on how «far» back it is on a drive. When I used a 500GB ssd, I had sda3/rootfs as the 3rd physical partition. Since my rootfs partition is 40GB and the first partition is a 1GB swap drive, with data partition in the middle as sda2, sda3 starts at (500GB - 40GB + 1GB) approx 461GB. This worked fine.
However on the 3TB original drive sda3/rootfs would start at 2961GB and that won’t boot. The solution was to (with a partition editor/manager) delete sda2, move sda3 to the left, right after sda1, then recreate sda2 partition after sda3. Mening that the physical layout on the disk is now [sda1/sda3/sda2]. And now it boots fine.

If you don’t want to mess around with illogical partition numbers vs actual physical placement on the disk, I presume the easiest is just to create a small dummy partition right at the start of the drive and have the data partition as sda4. (Assuming you’re using a seperate partition for data. Something like this [sda1/sda2/sda3/sda4] aka [dummy partition/swap/rootfs/data].

Man,

Stock u-boot has quite a bit of limitation.

I could try building a new u-boot for you and osa to overcome the limit of this box. But I need a volunteer who is interested in doing the testing.

-bodhi
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This is not a dealbreaker, it was just to put out the information in case someone in the future had a similar problem.
Of course, if you want to try to build a a new uboot, I am sure I could help you test, and probably others will too.

@Man i would suggest swap / rootfs2 / rootfs / data. Since it's easy to swap between active root '/' and only '/boot' must be on sda3 or sda5. Out of order GPT partitions are not so bad idea as well.

nicefile Wrote:
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> @Man i would suggest swap / rootfs2 / rootfs /
> data. Since it's easy to swap between active root
> '/' and only '/boot' must be on sda3 or sda5. Out
> of order GPT partitions are not so bad idea as
> well.
I don't know why one would need to have both rootfs and rootfs2?
For now I've settled on [dummy partition/swap/rootfs/data]. It works well for my Debian Trixie install, and is easy to replicate.

All,

I'm rolling a new u-boot for this box. Hopefully it will remove the shackle of not being able to save u-boot envs, and therefore have to self-impose a kernel size limitation of 5MB on SPI flash.

Please get these info.

Boot with serial console, interrupt u-boot countdown and,

printenv
help
bdinfo
md.l f1018000 8
md.l f1018100 1
md.l f1018140 1

-bodhi
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Forum Wiki
bodhi's corner (buy bodhi a beer)



Edited 1 time(s). Last edit at 11/01/2025 02:11AM by bodhi.

FYI,

The MVEBU kernel size is getting quite close to 5MB. I think the next kernel might not fit in the required flash space of 5MB for this box stock u-boot.

I've been trying to reconfigure this kernel at each version to keep the size down (just for this box), but there will be a time when that will not be possible.

-bodhi
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Forum Wiki
bodhi's corner (buy bodhi a beer)