Add BFO correction memory after shutdown

[EA2OY]

In my handheld, with v5 mod installed, i have the problem with a displacement in rx correct frecuency, because of that, all people sound like smurfs. If i go down with BFO correction to about .. -520, it sounds good.

When i reboot the walkie, i have to restart moving bfo mannualy, its annoying and so slow. i have take a look in google and there is more people with this issue, one mod its to build a faraday shield between speaker and si4732 module, but there is no way to close the handheld in this method.

I assume that every module have different rx missaligment so hold in the eeprom, for each band, the last bfo adjustment, or having any way to calibrate that, solves the problem.

Thanks a lot, EA2OY, 73s