Re: ISO installer image: GPT versus MBR partitions

["pelzflorian (Florian Pelz)" <pelzflorian@pelzflorian.de>]

It works, see end of this e-mail.

On Sat, Apr 20, 2019 at 12:50:49PM +0200, Thomas Schmitt wrote:
> So after these steps :
> 
> > I wrote guixsd-install-0.16.0.x86_64-linux.iso to my USB drive again.
> > Boot gets stuck again.
> >
> > I did `sudo dd if=/dev/zero of=/dev/sdc2` to zero out the EFI
> > partition.
> 
> mount the Debian Live 9 ISO (e.g. at /mnt/iso) and do
> 
>   dd if=/mnt/iso/boot/grub/efi.img of=/dev/sdc2
> 
> 

It still does not get stuck. :)



On Sat, Apr 20, 2019 at 01:16:14PM +0200, Thomas Schmitt wrote:
> My favorite suspect would be the partition table in Guix /efi.img.
> 
> To kill table entry 1 after having put the Guix EFI image back into
> partition 2 of the USB stick:
> 
>    dd if=/dev/zero bs=1 count=16 seek=446 of=/dev/sdc1
>

I did

sudo dd if=Downloads/guixsd-install-0.16.0.x86_64-linux.iso of=/dev/sdc
sudo dd if=/dev/zero bs=1 count=16 seek=446 of=/dev/sdc1

Boot gets stuck.

On Sat, Apr 20, 2019 at 04:23:49PM +0200, Thomas Schmitt wrote:
> Of course i meant  of=/dev/sdc2
> 

Oops, too late.


> If this does not help, then create a new empty FAT filesystem image,
> mount it, and copy the tree from the mounted Guix /efi.img into it.
> The new filesystem should have between 200 KiB and 1.4 MiB.
> (The Guix image of 1.4 MiB still has 90 % of its capacity free.)
> 

I do not recreate the USB drive.  I do:

qemu-img create -f raw fatfs.img 1M
mkfs.fat fatfs.img # from package dosfstools like the EFI system
                   # partition on Arch wiki
sudo mount Downloads/guixsd-install-0.16.0.x86_64-linux.iso /mnt/iso
sudo mount fatfs.img /mnt/img
sudo mount /mnt/iso/efi.img /mnt/efiimg
sudo cp -r /mnt/efiimg/efi /mnt/img/
sudo umount /mnt/img

> Then put the new filesystem into /dev/sdc2 and see what happens.
>

sudo dd if=fatfs.img of=/dev/sdc2
sync

Hooray!  It boots!  Thank you so much for your patience.

I remember back when I used Parabola GNU/Linux-libre, I had to make
sure I used mkfs.fat instead of mkfs.msdos or else the EFI partition
did not work, I think.

But…  Guix’ gnu/build/vm.scm already uses mkfs.fat.  Strange…

Regards,
Florian