What's the best course of action for this wall?

[theandroids]

Hey, I've removed some tiles in bathroom and damaged the wall. Plaster has come off, underneath I think its bonding plaster? Haven't a clue.
What would be the best repair method for the wall, also can I install tile backerboard without plastering the wall after the repair?

Any help is appreciated.

 

[bobasd]

why were the tiles removed?
is this over a bath or shower?
is the first photo a window reveal?

why not step back an photo the whole wall areas in question?

 

[ktuludays]

What you have exposed is plaster undercoat/browning.

It probably needs skimming