I wanted to update my old tablet, a Samsung Tab 2, to a more recent version of Cyanogenmod as it was beginning to act up a little. But now that Cyanogenmod is officially dead, the new overlord of Android ROMs is Lineage OS and that's what I installed. All went well and the tablet, now running Marshmallow, was stable and running smoothly. However, there were a couple of glitches.
Upgrading Sony's Xperia Ray from Android 2.3.4 (Gingerbread) to Cyanogenmod 10 (Jellybean 4.1) via Linux
So I wanted to upgrade my Sony Xperia Ray from its now old (and official) Gingerbread version of Android to the relatively more modern Jellybean. The most reliable alternative out there is Cyanogenmod.
While the Cyanogenmod wiki was generally useful, here's what I think is a cleaner guide. I performed the upgrade via a Kubuntu Trusty (14.04) laptop.
I recently upgraded a Motorola Defy to use CyanogenMod 7.2 as Motorola was not going to upgrade the phone from Froyo to Gingerbread. While the upgrade went reasonably smoothly and the phone is working well albeit with a few quirks, there was a major issue that I ran into recently. The phone loses its signal when it's roaming. Fixing this basically involves installing an (unsigned) app named Baseband Switcher, and setting the correct baseband for the phone.