Last summer I got a Xiaomi XiaoFang 1S camera from Magnus. Tried to get it working then but never succeeded but today I got some inspiration and managed to get it working and stream video over RTSP! It was not so hard. Just go to the GitHub project Xiaomi-Dafang-Hacks and follow the instructions but one must know that it was a T20L so start with those specific instructions.
One thing also that might have made a difference, now this time I did this on my Windows machine and not my Mac. And really made sure the SD card was formatted as a FAT32 drive.
Also found this firmware that looks interesting; OpenMiko
