Just a question.. about msx-cartridge HOT 1 OPEN

Perhaps you had written the ROM image to the wrong addresses.

The PCB is mapping the ROM memory in the 64KB address space of the cartridge slot as is. This means the address 0000h of the ROM chip corresponds to the address 0000h of the slot address.

The MSX, during BIOS boot, looks for a bootable program in every slot, but only on memory pages 1 (at 4000h) and 2 (at 8000h). If you had written your program on address 0000h, it will never boot.

Try to manipulate your ROM image such that it is extended to 64KB, so it contains:

• 0000h to 3FFFh: fill with zeroes
• 4000h to 7FFFh: your program
• 8000h to FFFFh: fill with zeroes

For a program that expects to run on page 1. Or the following if it expects to run on page 2:

• 0000h to 7FFFh: fill with zeroes
• 8000h to BFFFh: your program
• C000h to FFFFh: fill with zeroes

Then write that ROM image to the 39SF and try again.

from msx-cartridge.