The good news: B+ model of Raspberry Pi works with I2S DAC, e.g. RPi-DAC.
Just:
I made the kernel patch via Hex Editor - WORKS !
I can read the ARM opcode and know how the C-code looks as hex file ...
Customers getting RPi-DAC or RPi-DAC-RCA will get the kernel patch until the change will be available on Rasbian release.
How to wire and patch Rasbian for RPi B+