After applying 2V to the photon instead of 5V the device entered hard fault. The code is the same for a long time so no new modifications. Unable to enter safe mode, device reenters hard fault. After entering DFU mode, I did a particle update and a particle flash --usb tinker. Both commands appear to have been run succesfully but the photon remains in Hard Fault.
I am unable to enter setup mode or forget the existing Wifi credentials.
What would be the next step to try and recover it? (I have a STlinkV2 though I have never use it -if it might help)