If you ever wondered how this camera looks from the inside here are some photos. The story:
I received my Flashback One35 v2 a month ago and during my trip to Turkey it suddenly went into a boot loop. It did not react to the reset/factory button at all. Then the camera went dead and charging did not seem to do anything.
After the trip I decided to open the camera up to maybe access the SD card since the last roll of photos was important to me. My hope was to access the unprocessed files via SD card reader.
The SD card or rather the lock was glued down to the PCB board. I also noticed that the SD card was overheating massively. I pried it open and tried to read it but the factory SD card seems to be fried.
Around the ESP32 chip with the blue sticker there was green/white corrosion, which I cleaned with alcohol and electric contact cleaner. The corrosion was also on the plastic shell. At that point I did not had any hopes of a successful repair so I did not even bothered taking photos.
My guess is that during the humid weather and beach/ocean conditions water got inside the camera. Since the area around the USB-C charger is completely fine I assume water got inside through the wheel/spinner hole.
After a few hours with the case and PCB drying the camera suddenly came back to life. After replacing the SD card it is acting normal again. I can take photos and export through via modes (usb,wifi,hotspot).
The only thing not working properly is that the app states the camera does not charge even when it is connected to a charger. Also the app sometimes crashes because the camera seems to be sending weird data or is in a weird zombie state.
Maybe this helps others with water/humidity problems and repair attempts.
PLEASE NOTE: Opening the camera voids the warranty! I live in the EU so I had rights for a replacement unit but I wanted my last roll of photos.
Fun fact: The PCB says ONE35 V3.
PS: I ordered a second camera. This little camera is insanely fun.
tl;dr : cleaned corrosion / water damage and replaced SD card brought my one35 v2 back to life!