Thank you for taking the time to report this bug and contributing to Ubuntu. The count_bytes solution looks better to me. I see four dd calls in unmkinitramfs. Can you check those as well?
Debian is affected as well. If you can spare the time, please submit your patch to https://salsa.debian.org/kernel-team/initramfs- tools/-/merge_requests as well. ** Changed in: initramfs-tools (Ubuntu) Importance: Undecided => Low ** Changed in: initramfs-tools (Ubuntu) Status: New => Triaged -- You received this bug notification because you are a member of Ubuntu Touch seeded packages, which is subscribed to initramfs-tools in Ubuntu. https://bugs.launchpad.net/bugs/2055055 Title: unmkinitramfs: wrong and unneeded count= in a dd call Status in initramfs-tools package in Ubuntu: Triaged Bug description: Speaking about this line in unmkinitramfs: 113: dd < "$initramfs" skip=$start count=$((end - start)) iflag=skip_bytes 2> /dev/null | dd's block size is 512 by default. iflag=skip_bytes does not change that. Both $end and $start are byte-offsets. Hence the count is ($end-$start) blocks or ($end-$start)*512 bytes which is wrong. Anyways, the script just works because the count is unneeded: dd's output is piped into cpio which stops on the first end-of-archive marker, no matter how much data it is fed with. I think it is the best to just drop the count option (the patch is attached). If there is still a need to explicitly limit data fed to cpio, dd is impractical in this case. The only way to count= in bytes is bs=1, which makes dd extremely slow on lengthy data chunks. For example ubuntu-23.10.1-desktop-amd64.iso contains initrd with embedded uncompressed cpio archives of such sizes: 77312 7200768 78615040 A combo of dd+head could be used intead to skip and count respectively: 113: dd < "$initramfs" skip=$start iflag=skip_bytes 2> /dev/null | head -c$((end - start)) | Or even tail+head: 113: tail -c+$((start+1)) "$initramfs" | head -c$((end - start)) | To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/initramfs-tools/+bug/2055055/+subscriptions -- Mailing list: https://launchpad.net/~touch-packages Post to : touch-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~touch-packages More help : https://help.launchpad.net/ListHelp
