Some VGA does detect FPGAmstrad resolution just if pixels are ligther, so I turn them lighter during start of engine. Normaly a press into reset button (the one front the sdcard entry) does solve directly this problem (you can also turn on screen before MiST-board with this sort of screens)
I'm trying [http://github.com/mist-devel/mist-binaries/tree/master/cores/menu menu core project] with my stupid screen, as it normally I can power on MiST-board before screen for FPGAmstrad (switching core does the stuff here also)
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