shows a pattern with 16 levels of grey.
After overwriting the framebuffer with a value 255 for the first 100 lines I have the impression that the bar is brighter than the brightes square drawn by eips.
To overwrite the first, e.g. brightes square, with this ultra-white (255), one first has to overwrite it with a different value. Otherwise it won't update.
Crosschecking:
Filling the screen with bars of value alternating from 240 and 255 shows difference shades. (I assumed, that the upper 4 bit determine the grey level).
So, I have actually 17 levels of grey and I have to set background to 255 to get maximum contrast?
The background the home screen is actually as bright as the 255-bar.
Strange: Filling the screen with 0x10 and 0x00 bars, shows no difference. So using 0x10 to 0xf0 plus 0xff gives me again only 16 levels. But I see 17 different levels when overwriting the eips pattern.