Don't know the answer off hand - have you tried breaking this line down
PGM_P menu_pgm_ptr = (PGM_P)pgm_read_word(&(MAIN_MENU_LABELS))
(either in the debugger, or using printf's) to see what the value is at each stage on the respective platforms?
(Adding whatever modifiers/coersion to get the output to be the address, and probably want to make come out in hex).
What do you get if you do
I rushed out and bought ESP-01 and ESP-12 since they were too cheap to miss, but to be honest, I have scrapped them and just bought a CC3200 Launchpad, and so far loving the extensive ENGLISH documentation and reliability. Hands down, CC3200 beats ESP8266 in my opinion. Not to mention the $15 I wasted spent on the ESP modules before deciding they were not reliable or stable enough. Reliability is poor, they seem to 'hang' at any opportunity even though AT firmware 0.95 is 'supposed' to address the stability issues, it does not!
I am not saying the ESP8266 does not have masses of potential, what I am saying is, they are not yet market ready. I also suggested the support website considered an english section, that didn't even get a response!