ZFS-DKMS doesn't work on vanilla image https://dl.armbian.com/longanpi-3h/Bookworm_current_minimal
Image is freshly burnt to the SD card.

root@longanpi-3h:~# apt update
root@longanpi-3h:~# apt install zfs-dkms

root@longanpi-3h:~# modprobe zfs
modprobe: ERROR: could not insert 'zfs': Exec format error

root@longanpi-3h:~# modinfo zfs | grep -v parm
filename:       /lib/modules/6.12.23-current-sunxi64/updates/dkms/zfs.ko
version:        2.3.1-1~bpo12+1
license:        CDDL
license:        Dual BSD/GPL
license:        Dual MIT/GPL
author:         OpenZFS
description:    ZFS
alias:          zzstd
alias:          zcommon
alias:          zunicode
alias:          znvpair
alias:          zlua
alias:          icp
alias:          zavl
alias:          devname:zfs
alias:          char-major-10-249
srcversion:     2742833EE1C14D857611F06
depends:        spl
name:           zfs
vermagic:       6.12.23-current-sunxi64 SMP mod_unload aarch64

root@longanpi-3h:~# file /lib/modules/6.12.23-current-sunxi64/updates/dkms/zfs.ko
/lib/modules/6.12.23-current-sunxi64/updates/dkms/zfs.ko: ELF 64-bit LSB relocatable, ARM aarch64, version 1 (SYSV), BuildID[sha1]=f87455b001529d816f09e1498e63a902d1af9be5, not stripped

root@longanpi-3h:~# uname -a
Linux longanpi-3h 6.12.23-current-sunxi64 #1 SMP Thu Apr 10 12:39:41 UTC 2025 aarch64 GNU/Linux

logs

After doing apt upgrade, reinstalling dkms module result is the same.

Edited May 27, 20251 yr by Johnny on the couch
link

please show the output of "apt policy zfs-dkms"

 

but essentially, this looks the same as your other rodeo/struggle with this board and dkms.  As mentioned there, you are much better off with btrfs instead of zfs on your SBC.