Thx you 
Can i use boss v1.2 as a usb doc on a computer or mobile phone?
Good question. You may be able to but not without some DIY and programming work. The BOSS DAC needs an I2S interface (from the 40-pin header on the Raspberry PI) and also needs a device capable of operating in slave mode for the I2S clock signal, which the raspberry Pi can do.
You may be able to use a raspberry Pi zero and find a way to interface through that. It seems possible but not sure if anyone has done the work already.
All I found with a quick search is the link below
lifehacker.com/turn-a-raspberry … 1750112654
Thanks for replay . I dont have enough knowlegde for this .But could be good
Is there any chance to use the Boss with Asus tinker board?
Since the Boss DAC has it’s own clock signal generated on the DAC board it will only work with a computer board that supports slave mode (clock signal provided by the Boss DAC). The Tinker Board S added support for this so it may work but I don’t believe the original Tinker Board has this feature so it won’t work with the Boss DAC.
Allo, any ideas on how well the Boss v1.2 will work with the RPi 4?