Changes
/* LMMV */
* In P1 mode, LMMV seems to operate as if in bitmap mode.
* For 2bpp,4bpp and 8bpp, low byte of FC is always read for the colour. FC high byte remains the value from the last bitmap LMMV command. i.e. To set the upper byte of FC for P1 mode, set bitmap mode, set FC, and do LMMV command. From now the upper byte If x is even, you must set for P1nx to 2, if x is odd nx is min 1.
All of these explain why it is best that FC is filled with the same data for each pixel.
