ath79: Fix for Mikrotik NAND bad blocks - testers needed

[Sergey Ryazanov]

Hello Danijel!

On Mon, Mar 22, 2021 at 11:54 PM Danijel <danijel.tudek at gmail.com> wrote:
> I'm working on restoring Mikrotik RB2011 support after ar71xx target was
> dropped after 19.07 release. While working on it, the problem with bad blocks
> and the issue of the current way of flashing kernel was also brought up.
>
> Right now, for Mikrotiks we use kernel2minor which generates a 4MiB YAFFS2
> partition image holding the kernel binary.
> This method can't take NAND bad blocks in the kernel partition area into
> account, and if there are any, flashing fails and the device is usable only
> for RouterOS, because YAFFS2 support was removed from OpenWrt a few years ago.
>
> I was able to re-add YAFFS2 driver and limit it only to Mikrotik builds of
> ath79 target, and in my tests it properly mounts the kernel partition and
> replaces the kernel binary. However, I don't have a device with bad blocks in
> the kernel area so I can't confirm if it will properly handle them, although
> it should work unless the upstream driver (or Kconfig) is messed up.

Thank you for taking care of this. Missing of YAFFS2 support causes
more issues besides the bad block in the kernel area. E.g. 'large' and
'64m' images for boards with different block formats. So I am for
YAFFS2 support!

> So now I'm looking for testers (and reviewers) who could test this change on
> the affected devices (with bad blocks) and NOR Mikrotiks.

I have a couple of RB433 boards somewhere with BB in the kernel area.
I will try to find them and test with your changes.

-- 
Sergey