It's on an ATmega328.
Actually I can get 4, 2.66, 2.00 and 1.6 but it's pretty much a sub-multiple of the clock speed, hence me suggesting a change of crystal.
Crystals are cheap and it's not rocket science to replace one, but if you don't have the experience I'm not sure I should recommend you do it. I'd hate to have a dead Axon on my conscience
Frankly for $14 or whatever I'd just buy another BT module.
You said before that if you loop back Tx to Rx you get back from the BT what you send to it. Have you tried sending the clock speed AT command? If it works that has to be the best option. And you have nothing to lose.