I have flipsky 72150 outboard with integrated esc. I used the Vesc tool via USB and it worked fine. I did a bootload, changed some parameters etc. It connected, and I could use the arrow keys on my macbook to make it spin forward and reverse.
However it disconnected a few times, but connected again when switching off/on the batteries.
Now I cannot connect anymore, the UART still has 5 v and the ADC 3.3 v so I think it is not bricked.
What is the problem? frozen firmware?
Could I connect a bluetooth module to the UART and flash new firmware through my phone?
Thanx!

It's probably bricked. My vesc still read voltages on the ports when it was bricked, it's just that the stm32 chip doesn't know what to do with them so you have to flash it with an st link. BLE or UART doesn't work anymore so check if the vesc has swd pins available, if not, you'll have to dissassemble it and check for swd pads on the pcb and use a pogo pin spring connector to get contact on those and flash using the st link.
jozo
try bt and another pc not mac