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References: <CPT1K6SS7MJB.11OX1R7M79RF6@unicorn-x220.lan>
In-Reply-To: <CPT1K6SS7MJB.11OX1R7M79RF6@unicorn-x220.lan>
From: Konstantin Kulikov <k.kulikov2@gmail.com>
Date: Tue, 17 Jan 2023 08:44:37 +0300
Message-ID: <CAD+eXGQnGW-sW26dAEgypGj2-hePf9Y57WvdV7No3r5ArHucBw@mail.gmail.com>
Subject: Re: loading an apkovl from an external USB stick
To: Unicorn <unicorn@regrow.earth>
Cc: ~alpine/users@lists.alpinelinux.org
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initramfs-init calls nlplugfs[0] which finds apkovls on disks. Its
code[1] is a bit hard to understand, but it has many debug statements
so try to add "debug_init=3D1" to kernel cmdline and continue from
there.

[0]: https://git.alpinelinux.org/mkinitfs/tree/initramfs-init.in#n581
[1]: https://git.alpinelinux.org/mkinitfs/tree/nlplug-findfs/nlplug-findfs.=
c

On Sun, Jan 15, 2023 at 11:21 PM Unicorn <unicorn@regrow.earth> wrote:
>
> Hello,
>
> I am trying to learn to make proper use of the power of lbu and apkovl wi=
th my ARM SBC, but I am confused by a few things here.
> Firstly, the "apkovl" kernel cmdline option is quite poorly documented, a=
t least I could only find one somewhat complete documentation in the wiki, =
in the PXE boot article [0]. However I do not seem to be able to get one of=
 the mentioned formats to work.
>
> A bit of background: I have the generic ARM archive extracted to mmcblk0p=
1, so it boots from that partition. I then tried to save/load the apkovl fi=
le from the second partition, mmcblk0p2. I was able to achieve this with th=
e following kernel cmdline option:
> apkovl=3D/media/mmcblk0p2/myhostname.apkovl.tar.gz
>
> I assume that this only works because the partition is automatically moun=
ted there at boot. If somebody can also explain what determines which parti=
tions get automatically mounted, please enlighten me, because this is alrea=
dy quite confusing to me. :)
>
> Now I tried to save/load the apkovl from an external USB stick on the sda=
1 partition. I noticed that this partition does NOT get automatically mount=
ed in /media/, so the previous solution does not work. However the other fo=
rmats that are mentioned in the abovementioned article [0] also do not work=
. I tried the following:
> apkovl=3Dsda1
> apkovl=3Dsda1:vfat:/myhostname.apkovl.tar.gz
> apkovl=3Dsda1:vfat:myhostname.apkovl.tar.gz
> apkovl=3Dsda1:myhostname.apkovl.tar.gz
>
> These should work according to the explanation on that page, but do not.
>
> I asked on IRC and ikke linked the code of the initramfs-init.in file of =
mkinitfs to me [1], however I do not see support for this syntax in that fi=
le. So either the wiki is wrong here, or this is already handled by somethi=
ng else before the $KOPT_apkovl variable gets used by the script.
>
> I would really appreciate advice on how the automatic mounting of partiti=
ons in /media/ actually works and how the apkovl option is correctly used. =
I'll happily contribute my learnings back to the wiki. :)
>
> Thanks,
> Edin
>
> [0] https://wiki.alpinelinux.org/wiki/PXE_boot
> [1] https://gitlab.alpinelinux.org/alpine/mkinitfs/-/blob/master/initramf=
s-init.in#L42