A5_UL Eu single sim (and any compatible variants) Working ROM thread

Hi all.
I'm using CM12.1 5.1.1 from 20150429. Grarak unofficial ROM.
Any Cm12.1 based ROM newer than this has bugs making my phone unusable.
-long time detecting sim card, and long time getting a cellular connection once sim detected
-SMS not sending or receiving
-no calls incoming

Which basically make it a mini tablet :(...

So far I've tried a pacman 5.0.3 ROM but found it sluggish.

Does anyone with this same model of phone have a workaround or a suggestion of a stable working 5.1 ROM?
Has anyone tried updating RUU with either success or failures to report?
I'm at a loss here and its a shame, this phone is good value for money and was working well up to this last cm12.1 build.
I really don't want to go back to 5.0, and I'm not sure any sense/stock ROM is better? Can you share positive experience on this matter?
Thanks to all devs who give their time to allow us to use and own our phones. I am grateful and in no way taking any of this for granted.
Without you we'd all have locked phones and no freedom.
And peace to all, above and beyond ALL the rest!