Will try to find a solution, that works on all Pandoras. In the meantime, you could try adapting the shader Default.8bs in 'appdata/8blitter.lordus/plugins'.
if you switch
gl_Position = vec4(a_position.x, a_position.y, 0.0, 1.0);
to
gl_Position = vec4(a_position.y, a_position.x, 0.0, 1.0);
it should be rotated back.
If any of the directions is mirrored then, you could try adding -1* to either coordinate like:
gl_Position = vec4(a_position.y, -1.0*a_position.x, 0.0, 1.0);
Update:
I just saw an image of how it's rendered sideways, and adapting the shader won't work for that.