Arch Linux

ham

Member

Registered: 2016-11-25

Posts: 6

How to start unbootable installation?

Fresh install from bootstrap.

mmcblk0p1 is esp
mmcblk0p2 is swap
mmcblk0p3 is btrfs root

I tried this:

grub> set root=(hd0,3)
grub> linux /boot/vmlinuz-linux root=/dev/mmcblk0p3
grub> initrd /boot/initramfs-linux.img
grub> boot

Waiting 10 seconds for device /dev/mmcblk0p3
ERROR: Unable to find root device: '/dev/mmcblk0p3'.
You are being dropped to a recovery shell

ewaller

Administrator

From: Pasadena, CA

Registered: 2009-07-13

Posts: 19,774

Re: How to start unbootable installation?

It has been a while since I have used Grub.  IIRC, partition 3 becomes partition 2 in zero based Grub.  IOW, try (hd0,2)

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Trilby

Inspector Parrot

Registered: 2011-11-29

Posts: 29,523

Website

Re: How to start unbootable installation?

It's been a while for grub for me too - but I think only the drives are zero based, the partitions are one based.  But I don't think that is relevant.  What's been presented doesn't add up.  The p1 partition is where the kernel and initramfs are.  This is what grub needs.  Specifying that they are in the p3 partition at /boot/<whatever> is wrong.  *After* booting the p1 partition is mounted at /boot but at boot time, the boot directory of the p3 partition should be empty.

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"UNIX is simple and coherent..." - Dennis Ritchie, "GNU's Not UNIX" -  Richard Stallman

ham

Member

Registered: 2016-11-25

Posts: 6

Re: How to start unbootable installation?

with command "grub> set root=(hd0,3)" I can find kernel from /boot.
(hd0,2) got "unknown filesystem" and (hd0,1) "vmlinuz not found" when trying to load kernel.

ewaller

Administrator

From: Pasadena, CA

Registered: 2009-07-13

Posts: 19,774

Re: How to start unbootable installation?

Fair enough.  As I said, it has been a while

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Nothing is too wonderful to be true, if it be consistent with the laws of nature -- Michael Faraday
Sometimes it is the people no one can imagine anything of who do the things no one can imagine. -- Alan Turing
---
How to Ask Questions the Smart Way

Trilby

Inspector Parrot

Registered: 2011-11-29

Posts: 29,523

Website

Re: How to start unbootable installation?

Was the ESP mounted on /boot when you did your initial install?  If not, that's probably why grub is failing in the first place.

Basically you now have a unified boot and root (and a spare useless esp partition).  I don't think you should pass the "root=" parameter to the kernel in this case.  That partition is already mounted so there is no changeroot needed during init.

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"UNIX is simple and coherent..." - Dennis Ritchie, "GNU's Not UNIX" -  Richard Stallman

ham

Member

Registered: 2016-11-25

Posts: 6

Re: How to start unbootable installation?

Was the ESP mounted on /boot when you did your initial install?  If not, that's probably why grub is failing in the first place.

mmcblk0p1 was mounted to /boot/efi. 64bit install with 32bit efi, so install is tricky. You can make bootable Ubuntu install-media if you put bootia32.efi to efi directory. I haven't found way to get Arch install-media work with baytrail-devices.

I tried archboot media to install. That booted, but grub install failed.

seth

Member

Registered: 2012-09-03

Posts: 51,056

Re: How to start unbootable installation?

tried the fallback initramfs? (resp. ensured mmc support is in the standard initramfs)

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Trilby

Inspector Parrot

Registered: 2011-11-29

Posts: 29,523

Website

Re: How to start unbootable installation?

mmcblk0p1 was mounted to /boot/efi.

Ah, that makes sense.  Still, I removing the root parameter on the kernel line might help.

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"UNIX is simple and coherent..." - Dennis Ritchie, "GNU's Not UNIX" -  Richard Stallman