Having the exact same problem as the OP did when he started the thread.
Got a 148f:3070 ralink radio. ( DMG-11 , Power on by digital element ).Its a fine adapter and i wish i could make it work somehow.
Everything is updated , including upgrades,headers,dists and backports ( 4.4.2-1 ).
Followed the steps the OP posted to the letter but still it refuses to inject.Other than that it seems to work ok.It can connect to networks wirelessly,
enter monitor mode, airodump sniffs beacons , data ( although a bit slow ) , but injection test fails , always 0/30 no matter how many APs it finds.
Running Kali on Virtual Box , although it seems plugging the adapter after it boots and adding a usb filter with its prod/vend id ,
bypasses the common adapter problems with virtual box. I've spend a whole lot of time on this issue and
i am really close to buying a guaranteed-to-work adapter soon , so i beg for some help... Anyone.... :'- (
If there is a way to make it work , please help me...