Hallway wall diaster - unsure how to proceed

[Temmy]

What started as a small patch I hoped could be filled and sanded, was effortlessly scraped back to something a lot bigger

Honestly I couldn't tell you if it was originally lined with paper, or a terrible paint job, but that's the size of what scraped away easily.

The edges you can see have good adhesion.

Really unsure what to do about this. Should I just keep scraping the whole wall until it's all plaster and start fresh?

 

[Tigercubrider]

Yes.
If you're lucky then you may be able to cut a line upwards along the line of the door. And another in the corner? Sand the door line towards bare plaster

I think it's because the wall was painted with unthinned paint rather than a mist coat- allowing a sheet of paint to dry but not bond.

 

[Temmy]

Yes.
If you're lucky then you may be able to cut a line upwards along the line of the door. And another in the corner? Sand the door line towards bare plaster

I think it's because the wall was painted with unthinned paint rather than a mist coat- allowing a sheet of paint to dry but not bond.

The rest of it isn't scrapping away easily. Any tips on how to loosen it up?