Hello,
I've noticed that calling sceDisplaySetMode(0, 480, 272) (or whatever arguments are passed) produces the same result.
After a call to sceDisplayGetMode(&pmode, &pwidth, &pheight) for checking it returns 0, 480, 272. Also it returns the same values although sceDisplaySetMode() is not called. Is it normal?
To set a direct framebuffer is only needed a call to sceDisplaySetFrameBuf()... after that you can put the pixel info for display it immediately.
Note: I'm not using the Gu library.
Regards.