A few weeks ago I received the new pcb (ISA2442). Several things have changed with respect to the first pcb, so several software things had to change.

One of the main changes was the 640 x 400 pixel mode. On the first pcb, a byte from memory represents 8 pixels, and the byte tells for each pixel if it has foreground color or background color (these colors being programmable).

On this new pcb, a fetched byte has information for only two pixels (pixels last 40nS). So we can simply have 4 bits (16 colors) per pixel. The color of each of the 256000 pixels can be set independent from the others.

Today I got this new mode to work. 
On the picture you see mainly uninitialized memory, that gives a random, noisy pattern of colored pixels.
In the first row I programmed the 8 basic colors, and the second row shows the same colors with low intensity. So the upper two rows show all 16 available colors in this mode.

On the last row I made horizontal and vertical stripes, and a few checkerboard-patterns of two colors, that give the 
impression of another color (orange, and variants of green and blue).

You might ask why this is only 400 lines instead of the standard 480. This is because the processor can not run the user program during the active part of the video frame, because it is busy rendering the screen. By using only 400 lines, the processor has more time to run the user program.

The 320 x 200 pixel mode (used for the ZX Spectrum screen) was essentially unchanged.