You plug sequencer(1) on z80 clock and sequencer(0) on VGA... put another problem : VGA use 25MHz speed for scanning RAM. so Z80 have to use same speed yeah.
To solve this problem you can use a special RAM done for this problem, a RAM that you can WRITE at a certain speed, and READ at another speed, this magic component is called '''ramb16_s16_s16'''. Note that they have no problem to write simultaneously on two RAM componentcomponents, so that you can dump video RAM contain content using starter kit RAM, and you can display VGA using FPGA internal ramb16_s16_s16 RAM.
=== Bootloader ===