need to make new initramfs for new CPU. How to do it?

[ExecutorElassus]

So, I messed up everybody! I built a new computer -- new CPU, new mobo, etc., but with old drives -- and didn't recompile the initramfs for the new CPU architecture. Now I can't boot, because it gives me a kernel panic ("bad opcode," etc. etc.), I have a laptop, so I'm downloading an ISO of SystemRescueCD to boot into. Here's my problem:

I have /use and /var both inside a RAID array on an LVM. From what I've seen, "better initramfs" (here) does not support pre-mounting /var from separate LVM.

So once I'm booted into SystemRescueCD, what initramfs do I need to use? From what I've seen, busybox no longer works, because some of its dependencies can no longer be built with static-libs (am I wrong about that?). What other options are there?

Thanks for the help!

EE

[soundrolf]

You can do it with:

[ExecutorElassus]

Here's the problem: I upgraded from an AMD FX chip to a Ryzen. The new machine won't boot. I've booted onto a SystemRescueCD on a USB drive, but I can't chroot into the old environment because /bin/bash doesn't work on the new machine. Is there a way to chroot into the old filesystem while still using the /bin/bash from the usb drive? I need to re-emerge … well, probably my entire system set, but I can't do that on a different machine (nor can I do it on the old machine, because the HDDs and some other parts are in the new one now).

Thanks!

EE

[soundrolf]

[pingtoo]

[ExecutorElassus]

I can boot the machine from SystemRescueCD and get to a prompt. I can mount all the drives and everything. What I can't do, at this point, is chroot into the old filesystem on the new architecture.

what changes do I need to make to [newroot]/etc/portage/make.conf for the new architecture? What tools do I use to find this information?

Assuming I just do a fresh install: I can download the stage3 tarball and just unpack it into /mnt/gentoo, right? How much of my old config do I need to back up? Or is it enough just to unpack the tarball, and use that to emerge the system files to get it to the point where it's bootable?

Cheers,

EE

Follow-up: is this guide a reliable one? Because if that's the case, I can also just rebuild system packages on a rescue partition and copy them over. Or is it better to unpack a stage3 tarball onto my broken system?

[soundrolf]

[ExecutorElassus]

Hi sounroif,

I can't install programs (in this case, cpuid2cpuflags) until I can chroot. Should I just comment out the line for the CPU_FLAGS in make.conf? Is CFLAGS="-mtune=native -O2 -pipe" correct?

so, copy /mnt/gentoo/etc/portage somewhere safe
cd /mnt/gentoo
wget [tarball]
'tar xpvf stage3-*.tar.xz --xattrs-include='*.*' --numeric-owner'

restore /mnt/gentoo/etc/portage

and then I should be able to chroot?

Cheers,

EE

[pingtoo]

• Boot into SystemRescueCD shell
  
• Mount old drive's rootfs to /mnt/getoo
  
• cp -rp /mnt/gentoo/etc/portage to /some/where/writable/
  
• Mount rest partitions
  
• Mount all pseudo file systems, i.e. /proc, /sys, /dev (if you use devtmpfs)
  
• untar stage3 into /mnt/gentoo
  
• cp -rp /some/where/writable /mnt/gentoo/etc/porage
  
• update /mnt/gentoo/etc/portage/make.conf, set COMMON_FLAGS="-march=native -O2 -pipe"
  
• cp /etc/resolve.conf /mnt/gentoo/etc/resolve.conf
  
• chroot /mnt/gentoo
  
• emerge -a @world
  
• emerge genkernel
  
• genkernel all --menuconfig
  
• verify /boot got the new kernel and initramfs
  
• configure boot loader use new kernel with initramfs
  
• reboot

Use -march=native should give you correct CPU setting for your new CPU.

[soundrolf]

This is my make.conf

[ExecutorElassus]

quick question about genkernel: can the initramfs it generates deal with /var (in addition to /usr) being on a software RAID LVM? The preamble here suggests it can, but the page for genkernel itself doesn't mention it.

I don't want genkernel to configure/build the kernel, nor configure GRUB. I do that myself manually. Can genkernel work like that?

Cheers,

EE

[NeddySeagoon]

ExecutorElassus,

You will need to rebuild most of the system set for the new hardware.
busybox is still good with static linking but. lvm is not.

You can't chroot in with a broken system, but you can rebuild things with a parallel system to make binpkgs, then install the binaries.
You need Fix My Gentoo.
_________________
Regards,

NeddySeagoon

Computer users fall into two groups:-
those that do backups
those that have never had a hard drive fail.

[pingtoo]

Yes, genkernel generated initramfs can mount /usr, /var. But you will need to create a file name /etc/initramfs.mounts in /mnt/gentoo and the content are

[ExecutorElassus]

Hi Neddy!

is the method outlined by pingtoo and soundroif not going to work for my use-case? If I can unpack a stage3 into my mounted filesystem, shouldn't that provide me with a working bash and gcc, from which I can then emerge all the rest? (after, of course, I copy /mnt/gentoo/etc/portage back over from the backup).

Cheers,

EE

[ExecutorElassus]

update: I unpacked the tarball onto /mnt/gentoo, chrooted, and then tried emerging world. This failed on bzip2, which gave the error that there was an illegal instruction in libbz2.a.

So what did I do wrong? I'm chrooted into the new system, but can't emerge anything. What next?

Thanks for the help,

EE

[pingtoo]

Could you please chdoot into newroot and do

[pingtoo]

.a (dot a) file usually content elf object files. It is a passive archive file, so I have hard time to imagine how is illegal instruction in libbz2.a error. Is this a link produced error?

have your tried with

[NeddySeagoon]

ExecutorElassus,

Unpacking a stage3 into your existing install will destroy your world file and all your settings.
You can unpack a stage3 somewhere else and quickpkg the packages you need.

Illegal instructs or symbol version error?
I've seen the latter with bzip2 because the underlying glibc was too old. It only happens with binary mix and match.
You are doing a binary mix and match. The stage3 is running on top of boot media glibc and so on.

It its really an illegal instruction, there will be more info in dmesg.
_________________
Regards,

NeddySeagoon

Computer users fall into two groups:-
those that do backups
those that have never had a hard drive fail.

[ExecutorElassus]

Hi Neddy,

oh dear. well, then I've lost my world file and settings. I don't mind the world file, but it's going to be annoying trying to recover settings.

So now I'm following the Fix My Gentoo instructions, but I don't know how much stuff I actually need to build (since I no longer have my old world file). I did preserve /etc/portage, but nothing else.

My worry now is that I'm going to run out of space on /var before I can build enough packages to get a bootable system. What packages (or set) do I minimally need to get it bootable and able in install the rest?

Cheers,

EE

[NeddySeagoon]

ExecutorElassus,

You need the system set, kernel and initrd and a boot loader to be able to boot.
I guess that your /var/db/pkg/ has been overwritten too?

Do you still have the original /var/log/emerge.log?
That's every every emerge the box ever did.
_________________
Regards,

NeddySeagoon

Computer users fall into two groups:-
those that do backups
those that have never had a hard drive fail.

[pingtoo]

@ExecutorElassus, I am sorry I miss the world file.

[ExecutorElassus]

Hi Neddy,

I tried installing the kernel using the Fix My Gentoo instructions, /var filled up to 100%, and when I chrooted back to /mnt/gentoo to try `emerge -K sys-kernel/gentoo-sources` it seemed to work, but now I can't emerga anything else. I get an error that emerge can't find libffi.so.7.

So now what do I do? Do I have to install packages with tar? What package would I need to install with tar to get emerge working again?

/var/db/pkg is still there, but I can't read /var/log.emerge.log. ls reports it has a filesize of 37585896, though.

Thanks for the help. What should I do next?

Cheers,

EE

update: I tried using the tar command on a few files, getting "trailing garbage after EOF" notices for them. Now ls doesn't work, because it can't find glibc-2.34. So now the system is horribly broken. I can emerge binpackages on the live environment, but I can't use emerge to install them from the chrooted /mnt/gentoo. What exact order of packages do I need to install (using tar from Fix My Gentoo) to get it into a workable state?

update2: I had a binpkg of glibc, so I could use tar on that and get ls working. So now what should I do? I have a sizable number of binpkg files, but can't use emerge. should I use tar on the ones I have first, and then clear out /mnt/gentoo/var/cache/binpkgs/, and then emerge the system set on the rescue partition? Or should I proceed in some other way?

[pingtoo]

[ExecutorElassus]

well, what I think I need to do is wipe /var/cache/binpkgs/, chroot back into the rescue partition, emerge all of @system, and then libffi-compat just in case, exit back out, chroot into /mnt/gentoo, and try using tar to install all of that stuff manually. Last time I checked it was about 50 packages, so it should be possible without too much suffering.

But I'm not sure if this is the right way to proceed. Maybe Neddy has other suggestions.

Cheers,

EE

[NeddySeagoon]

ExecutorElassus,

The idea of a the rescue install is that it uses your existing distfiles, so it does not need to download anything and your existing binary packages space.
The rescue install, its distfiles and binary packages can be anywhere you have space.

Using your original or corrected /etc/portage makes like easy as portage will reject binaries built with the wrong USE flags.
Scatter the bits of the rescue install where you have space. As long as you tell portages where they are.

A long time ago I did unpick the liveDVD
The relevant bit here is section 5 and what was needed to get a working chroot. That page is from 2009, so versions will have changed.

Bash just needs ...