bad news. The retro market is flooded by rebranded v9958 fake chips. I bought six already from different Aliexpress stores and all came with the same serial and "notch". As we know, the package of yamaha v9958 has no notch. (Example on figure bellow)
For while, I tried those six I received from Aliexpress stores. All have the same code and manufacturing date:
It seems that the are rebranding "toshiba" 64 pin ics like 68000 or 1253. Compare for yourself....
Unfortunately, this is leading to a price dispute and ruining the MSX2+ spare parts market. And this project is stopped waiting for a part that works.
My first v9958 was about 10 usd on august, 2022. ... Today (march, 2023) I got a quote of 111 usd from utsource.