NEW WAYI made this quick video to show how to fix a bug with BoB not building startps files, using Miguel's techniques for Attila. I also go from making a minor nation playable just as an example. Sorry for the cruddy audio and lack of script. Don't have a lot of time these days so had to do it quickly. If there's any demand I'll make a separate video showing just making factions playable.
https://www.youtube.com/watch?v=mI1q...ature=youtu.be
‹OLD WAY - No longer required to edit script
A huge thanks to Samio who discovered this!
Samio stumbled across something very interested today. If you comment out or delete lines 672 to 751 (the SAVING / LOADING section) in lib_misc_campaign.lua, custom factions seem to work just fine!
Strangely enough, saving and loading seems to work fine too.
The standard faction unlocking procedure is still the same, so you'll need to create the political parties, and change some faction values from false to true. I don't have much time at the moment so I can't expand but tutorials from previous games show you what you need to edit.
There are still limitations such as no cultural features but the only crash I've had is clicking the 'assign provincial governers' pop-up. Assigning governers and estates manually works fine though.
another possible limitation I've come across is a limit in the number you can unlock at once. I can't say for certain as I may have made a mistake but after unlocking all Welsh factions I moved onto vikings, but only half of them appear in the campaign menu. More testing is definitely required.
I've attached below a pack file with all Welsh factions unlocked and some Viking factions. Be sure to thank Samio if you end up making the next 'all factions playable' mod!