Black wavy bgd on 2.71 emu firmware
If you use devhook to emulate 2.71 firmware, you can have a black wavy background.
Enter this folder in yor dump: E:\DH\271\FLASH0\VSH\RESO URCE
There you will see some BMP files and some other stuff.
Take any of the 01-12 BMP files and rename it to, for example 13.BMP(I prefer taking 01.BMP).
Open it and change the color to black and then save it as the one you renamed(in my case 01.BMP)
When you boot up your 2.71 emu, go to Themes and the first one will be black.