Comment 32 for bug 50437

As ubiquity is using live-cd / preinstalled, initramfs-tools preinst is not run.
Ubiquity simply parses /proc/swaps, finds largest partition and writes out /etc/initramfs-tools/conf.d/resume.
http://bazaar.launchpad.net/~ubuntu-installer/ubiquity/trunk/view/head:/scripts/plugininstall.py#L835

Thus in install/upgrade/reinstall cases with ubiquity it should all just work correctly. But indeed if one manually modifies/recreates swap partition one must at the moment do the following:
1) adjust /etc/fstab with new UUID
2) adjust /etc/initramfs-tools/conf.d/resume with new UUID
3) update-initramfs -k all -u