Arch Linux

This might be very non-trivial, but I'd love to see a way to create an ISO, based on the packages released at a previous time. I'm trying to create a customized archiso for my second time (previous was months ago), and both times my unchanged releng ISO fail to boot for different reasons, that I've been unable to diagnose. Again, this is without changes to the releng files, just as a starting point. I assume the issue is due to package versions being available when I run archiso that weren't released yet when the official ISO was built.

I'd love to be able to specify the exact timestamp used on the latest officially released archiso, make sure I make an ISO that works, then binary search out where it fails.

The current failure I'm getting is discussed at: https://bbs.archlinux.org/viewtopic.php?id=208034 --- It's a combination of "dmi: Firmware registration failed.", "Initramfs unpacking failed: junk in compressed archive", and "Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(0,0)".

I assume this is due to a change in the linux package, because when this month's ISO was released, linux 4.3.3-2 was most current in core, and now it's 4.4-3.

But, I'd love to be able to confirm it, and figure out exactly which release is causing the error.