that seems rather strange, it seems to fail when reading the root block pointer. could you do the following:
re-run the "ls" in grub to get the current DVA values, the following line directly before the checksum verification fails:
now, without importing the pool, reboot in the installer rescue shell and run the following (replacing all three DVA offsets with the numbers obtained in Grub):
Code:
for offset in 13005bb90 9418 188001ac0; do zdb -e -R rpool 0:$(python3 -c "print(hex(0x$offset << 9))"):800 > out_$offset; done
save the resulting out_* files and post them here together with the new logs.