My circuit has both 8K SRAM and 8K EEPROM
Why not get a uC with 64k (or more and use banking) instead of creating exotic inventions.

The '51 was originally designed as a ROM based architecture and, while Updating flash to a newer revision by ISP/IAP definetely is a godsend, what you propose iw Waaaay beyond what you should ask a '51 to do.

Yes, it can be done, but the first purchase (if you absolutely will not use a 64k derivative) should nbe a family size bottle of aspirin.

Again, what you propose is not needed, you can pop another chip in and have 8 times as much code memory. That chip will cost you less than the aspirin to get your scheme going.

Erik