inside corner on drywall

[FredrikR]

Do you need such a metal angle bracket in inner corners if you are going to install both OSB and gypsum?

A thin line of acrylic sealant works well in inner corners.

 

[Mikael_L]

Do you need such a sheet metal bracket in the inner corner if you are going to install both OSB and plasterboard?

Either support from studs that fix the boards properly in the corner, or a sheet metal bracket is probably recommended. Otherwise, the boards will slightly gap in the corner and crack the paint or wallpaper, making it look bad later.

In this thread, a bit after the middle, I join the discussion and explain how I do it and why, and include some pictures.
https://www.byggahus.se/forum/threads/innerhoern-pa-gipsskivor.105192/
An additional reason for my method (in combination with cross-bracing on the inside of the outer wall) is to facilitate electrical wiring.