After writing a byte/page to EEPROM poll the status bit and wait for writing to be finished. Then write the next byte/page.

Make a small Rx buffer about 64 bytes in data RAM and put the received bytes to buffer. When buffer full, write data to eeprom and then acknowledge it to master PC and request the next 64 bytes. This concept has proven to be acceptable and runs OK. I have used it in a few of my applications.

Franc