Excessively slow boot process after moving swap partition

I have installed Zorin Education Lite 15.3 32bit on my old Thinkpad T43p onto the HDD. The setup was a separate partition for /, swap, /var, /var/log, and /home in that order.

Then I thought I‘ll try to speed-up the machine by installing an SSD for the root file system and keep swap, /home, /var, and /var/log on the HDD (and moving it to the Ultra-Bay slot).

Everything went well, and the system now really comes up, applications start much faster.

Next I wanted to reuse the space on the HDD that held the old root partition. The first step was to delete the old root and swap, and redefine the swap partition at the start of the drive (leaving alone the other partitions for the moment.

So the steps were: swapoff, delete old swap, create new swap, and swapon, and finally change the UUID of the swap partition in /etc/fstab.

After reboot, the system seemed to hang, but using the recvovery mode, I found that the system has got problems at step Begin: Running /scripts/local-premount, and then many times floppy: error 10 while reading block 0, each with a huge time difference. Then after about a minute or two, the rest of the boot process continued with normal speed.

Googling lead me believe the problem is with the changed UUID of the swap partition. I followed the recommendations in this thread

The good thing: It solved the problem.

The curious thing: There was no file /etc/initramfs-tools/conf.d/resume on my system. Hugh? Desperate as I was at that point, I created such a file and wrote „RESUME=none“ as its content. After generating the new initramfs, the system boot was back to speed.

The reason for posting, despite the fact that the problem is gone: I‘m curious and can‘t stand it not to understand the original cause. Why? Because knowing might help me avoid the problem in the future. So, can anyone explain, why the boot process was delayed even though there was no RESUME=UUID=old-swad-uuid flag to point to some non-existing swap partition.

Bonus question: Except from the steps described above, what is required to move the swap partition?