MSX HDMI mutlimedia card

Regarding the updates, I'm still moving the site to the new host provider. Takes too much time....
Also was recently working on a beefed-up version of the same card, which is at layout stage completion

Thank you, I try my best. Also as any amateur I have very significant time constraint (I hope everyone understands).
Also I don't want to deliver something complex, which will be also not well tested and not very stable (could cause a huge disappointment). Hence, it took me some time to get the stable operation, improve the manufacturing simplicity (i.e. after assembly no tuning is required, no pots to be adjusted, despite complex analog design of the PLL).
Also it was noticed, that the FPGA capacity can't fit the whole machine design with all bells and whistles, hence I have changed the FPGA and increased its capacity from Xilinx XC6SLX9 to XC6SLX45. The "light" good old version of Procyon will be also available on 2 layers PCB, but the "heavy" version will use FPGA in the BGA package and 4 layers PCB. The heavy version is in the works for about a year, but I was hesitating to push ahead with that. Otherwise both have identical look and peripheral set.

Exactly right.
But still "light" version (demonstrated) has no possibility to lift the full 2+/TurboR alone. Everything but the CPU.
So, whoever gets the original Procyon with XC6SLX9 FPGA will have to use it in conjunction with the original MSX machine (no stand alone 2+ or turbo R).
I've emptied the FPGA and moved all the auxiliary functions including YM2413 emulation, USB keyboard support, FPGA configuration, SDcard I/O and MIDI to STM32F4 microcontroller (Cortex M4).
But still ironing up the uC FW. Currently working on the FPGA programmer such that user can read the FPGA image from the SD-card and program it into the EEPROM without any additional tools.

FPGA holds V9958 emulation, SCC, PSG, HIFI audio mixing, RAM emulation and cartridge emulation.
I've moved YM2413 soft emulation to Cortex M4. I.e FPGA intercepts the port access to YM2413 and sends the register writes to the sound engine in uC. Then the data is processed, effects are added (reverb, chorus) and then the data is sent back to the FPGA for audio reproduction and mixing.

IMHO, once I have a stable operation of the DFU (device firmware upgrade), then I'll be able to deploy the first batch.

I see.
The problem which I also experience here is well discussed on this forum pages. The MSX standard till MSX2 assumed to have an external VDP substitute in the 0x80-0x8B I/O address range. So, by using the MA20 similar technology currently I can only upgrade MSX1 to MSX2.
However, starting from MSX2+ and beyond, it seems like the alternative VDP address set is not consulted when the game starts. So, I'm still evaluating the possibility to intercept and dynamically replace the VDP access code when emulating 2+....
Bottom line - MSX1-> MSX2 upgrade is quite seamless... However MSX1->MSX2+ is more difficult due to the titles not respecting the good and old rule to consult the BIOS addresses....
So, this part still requires some additional software development.

Don't worry, that is the main issue for any amateur software / hardware developer: the time. I can understand perfectly, my game is going slower than expected due to time problems

Good luck and be patient!