This is great investigation all! Let me try to answer some of the questions (sorry if I miss any).
The RGB data does seem to be RBG, the RGBA, I’m notsure. You said unsigned?
Yes! Unsigned, specifically UNSIGNED_BYTE. Here are the parameters that are passed in to create the surface that this texture is supposed to be being extracted from:
{
color_texInternalFormat = LOCAL_GL_RGB,
color_texFormat = LOCAL_GL_RGB,
color_texType = LOCAL_GL_UNSIGNED_BYTE,
color_rbFormat = LOCAL_GL_RGB8,
depthStencil = LOCAL_GL_DEPTH24_STENCIL8,
depth = LOCAL_GL_DEPTH_COMPONENT24,
stencil = LOCAL_GL_STENCIL_INDEX8
}
so the next piece of the puzzle: if you access sailfishos.org from the normal browser, does it render OK?
Yes! In the browser it renders like the image on the left:
The file sizes match perfectly for 1080x2520x(3 or 4 depending on the file)
This may be a red-herring as I’m specifically filling a buffer of this size. So it could be that each pixel is more bytes and I’m only grabbing part of the image to fill the buffer.
This is making a great puzzle … just need to figure out how to put the bits together
It’s a puzzle alright 
My current working assumption is that the image is corrupted (maybe I’m grabbing some random texture memory?), so bear in mind there might not be a solution here if that’s the case. But I’d love to be proven wrong!
