As it happens, my pc shut down during an update.
I first tried some combination of https://wiki.archlinux.org/title/Pacman#Fixing_an_unbootable_system_caused_by_an_interrupted_upgrade, https://wiki.archlinux.org/title/Pacman#pacman_crashes_during_an_upgrade and some advice from arch forums, but I didn’t really know what I was doing at first, I might not have mounted everything properly, maybe it caused more harm than good?
Anyway, now I’m at the stage where even pacman from live iso without chroot reports crashes when trying to reinstall some packages:
[liveuser@eos-2026.01.12 ~]$ mount | grep /mnt
/dev/nvme0n1p2 on /mnt type ext4 (rw,relatime)
/dev/nvme0n1p1 on /mnt/efi type vfat (rw,relatime,fmask=0022,dmask=0022,codepage=437,iocharset=ascii,shortname=mixed,utf8,errors=remount-ro)
proc on /mnt/proc type proc (rw,relatime)
sys on /mnt/sys type sysfs (rw,nosuid,nodev,noexec,relatime)
efivarfs on /mnt/sys/firmware/efi/efivars type efivarfs (rw,nosuid,nodev,noexec,relatime)
securityfs on /mnt/sys/kernel/security type securityfs (rw,nosuid,nodev,noexec,relatime)
cgroup2 on /mnt/sys/fs/cgroup type cgroup2 (rw,nosuid,nodev,noexec,relatime,nsdelegate,memory_recursiveprot,memory_hugetlb_accounting)
none on /mnt/sys/fs/pstore type pstore (rw,nosuid,nodev,noexec,relatime)
bpf on /mnt/sys/fs/bpf type bpf (rw,nosuid,nodev,noexec,relatime,mode=700)
debugfs on /mnt/sys/kernel/debug type debugfs (rw,nosuid,nodev,noexec,relatime)
tracefs on /mnt/sys/kernel/tracing type tracefs (rw,nosuid,nodev,noexec,relatime)
configfs on /mnt/sys/kernel/config type configfs (rw,nosuid,nodev,noexec,relatime)
fusectl on /mnt/sys/fs/fuse/connections type fusectl (rw,nosuid,nodev,noexec,relatime)
dev on /mnt/dev type devtmpfs (rw,nosuid,relatime,size=15869972k,nr_inodes=3967493,mode=755,inode64)
tmpfs on /mnt/dev/shm type tmpfs (rw,nosuid,nodev,inode64,usrquota)
devpts on /mnt/dev/pts type devpts (rw,nosuid,noexec,relatime,gid=5,mode=600,ptmxmode=000)
hugetlbfs on /mnt/dev/hugepages type hugetlbfs (rw,nosuid,nodev,relatime,pagesize=2M)
mqueue on /mnt/dev/mqueue type mqueue (rw,nosuid,nodev,noexec,relatime)
sys on /mnt/sys type sysfs (ro,nosuid,nodev,noexec,relatime)
[liveuser@eos-2026.01.12 ~]$
[liveuser@eos-2026.01.12 ~]$ sudo pacman --root=/mnt --cachedir=/mnt/var/cache/pacman/pkg -S glibc
warning: glibc-2.43+r5+g856c426a7534-1 is up to date -- reinstalling
resolving dependencies...
looking for conflicting packages...
Package (1) Old Version New Version Net Change
core/glibc 2.43+r5+g856c426a7534-1 2.43+r5+g856c426a7534-1 0.00 MiB
Total Installed Size: 48.91 MiB
Net Upgrade Size: 0.00 MiB
:: Proceed with installation? [Y/n]
(1/1) checking keys in keyring [---------------------------------------------------------------------------------------] 100%
(1/1) checking package integrity [---------------------------------------------------------------------------------------] 100%
(1/1) loading package files [---------------------------------------------------------------------------------------] 100%
(1/1) checking for file conflicts [---------------------------------------------------------------------------------------] 100%
:: Processing package changes...
(1/1) reinstalling glibc [---------------------------------------------------------------------------------------] 100%
Generating locales...
ja_JP.UTF-8... done
zh_CN.UTF-8... done
en_US.UTF-8... done
pl_PL.UTF-8... done
Generation complete.
/tmp/alpm_or0moA/.INSTALL: line 1: 30095 Segmentation fault (core dumped) ldconfig -r .
error: command terminated by signal 11: Segmentation fault
:: Running post-transaction hooks...
(1/3) Arming ConditionNeedsUpdate...
(2/3) Checking which packages need to be rebuilt
foreign patool
foreign python-fvs
foreign python-pathvalidate
foreign python-setuptools-reproducible
foreign vkbasalt-cli
(3/3) Updating the info directory file...
[liveuser@eos-2026.01.12 ~]$
How can I do anything about that? Is this https://wiki.archlinux.org/title/Pacman#By_manually_extracting my only option now? Also, isn’t pacman --root supposed to use tools from outside of the --root?
All it took was posting this post plus a couple of hours of trying.