Here are some links I found usefull to mod my (chinese) RTXs:

• Baofeng DM 1701 / DM 1801 --> Opengd77. This is the famous DMR firmware that lets you convert these DMR RTXs into some more ham-friendly ones, and lets you use it as a MMDVM modem to build up long range simplex DMR HotSpots.
• Quansheng UV-K5, UV-K6 (or UV-K5 8), UV-K5 (99), UV-5R Plus --> IJV Mod. This firmware has been coded by IU0IJV, and Italian ham radio operator. You will have an FM RTX that can listen from 18 MHz to over 1GHz in AM, FM, DSB. It's got a fine tuning bandwidth function, control over RF gain, transmission in DSB (it lets you even transmit outband but do not do it: the RTX's hardware is not made to act outside its band and will shoot spiurious emissions everywhere with only a residual power on the frequency you chose). It can peform partial scans (you can define scan edges). From version 3.30 it'd be selectives capable.
• Tidradio TD-H3 --> Nicsure Mod. This mod lets you expand this RTX's capabilities.
• Tytera MD380 (NOT the UV 380)--> MD380 Tools. This mod lets your DMR RTX have a better ham feeling (for example you can set TGs on the fly). Another site explaining how to enable M17 encoding.

Here are some other projects:

• D-STAR call routing ports
• PI-STAR HotSpot
• WPSD = WPSD Plausibly Stands for Divergence HotSpot

I'm also aware that people are more interested in threads if there are kittens and potatoes.