Frida - look at your test results again - your logs above show the problem occuring!
You started with the first two bytes on the EEPROM being [99,55], then you wrote [55,99] to those bytes - and then read it back out and those two bytes were still [99,55] - just like what I see: Write doesn't work!
Espruino is a JavaScript interpreter for low-power Microcontrollers. This site is both a support community for Espruino and a place to share what you are working on.
Frida - look at your test results again - your logs above show the problem occuring!
You started with the first two bytes on the EEPROM being [99,55], then you wrote [55,99] to those bytes - and then read it back out and those two bytes were still [99,55] - just like what I see: Write doesn't work!