Atari 2600 vertical scaling bug:

[Firebrandx]

The internal footprint the 2600 core implements is based on 238 lines instead of 240, causing the set labels for vertical integer scaling to improperly stretch the graphics based on 240 lines. The current workaround is to multiply 238 for the integer you want and use that as a custom vertical scale. Example:

238 x 5 = 1190, so you have to use 1190 for perfect 5x vertical instead of 1200.

[tjanas]

Could you re-test with the latest JB firmware? https://github.com/analoguejb/Analogue-Nt-Mini-Noir-JB

If the issue is still present with JB V6.7, could you open a ticket at that other GitHub?