Hey guys.... a little late to the party, but hopefully I can give you some hope for custom dev....
I bought a kestrel as a temporary replacement for my Sony Z1 Compact which is being repaired... I was pretty shocked at the lack of dev... it's a great phone, amazing buy at £90!
It's not easy to develop for a phone with little support from the manufacturer, and lack of resources available on the web....
Due to the issues above and the lack of a source for a recent Android version, I won't be building a ROM from scratch with only Jelly Bean source....
BUT, I am working on a hybrid 4.3 ROM for the Kestrel.... woo hoo!
Have the kernel source, (am not far from compiling an unsecured kernel...), system, boot and recovery images....
Aiming for:
Pre rooted
Custom kernel (unsecured)
Custom recovery - CWM or TWRP (unofficial). Haven't decided which yet....
Remove bloatware
The framework will be based on stock, not up for compiling custom on 4.3 (to old).
I have a full time job and a family, so will be working on it when I'm able to... please don't expect a release to soon - I'll keep you updated....
Have attached a few screenshots of how it looks so far.....