This solution does not fix the problem of "stupid screen", but reveals something interesting about the defect (next chapter)
===== VIDEO: TODO : SAMSUNG 16/9 tests =====
Using lighter pixels full white screen during bootload show me that screen doubts between two positions : a perfect centered 4/3 with 6.5 centimeters horizontal border each; and a starting 16/9 at left, crop at 6.5 centimeters left.
* one time screen does crop at 6.5 left and right, changing the screen vertical position using menu does translate the image cropping left and right at fix position : 6.5 centimeters fix black border. About extra 1 centimeter pixels : image in middle of image does move, but not the borders at all.
* a second time image does move perfectly (completely/totally) left and right without crop, and if centered has 6.5 black border left and right. This time image seems complete but crushed.
During ZX-Uno merged, I found two bug on VGA implementations (true ones ?), first being horizontal and vertical counter not reaching VTot/HTot (one clock tic missing), and second the horizontal counter limited to 1024 not reaching HTot that seems more than 1024. Perhaps, if this bugs are valided as it, do go back on original 800x600@72Hz modeline formula.
==== DSK ====