Error when saving to flash

I just had this issue in a 1v91 flashed puck (not the Uncaught Syntax error, but disconnections on save() and E.setBootCode()). I can reset() just fine, but it still crashes on save(). Can't remember what exactly I did to trigger this, but I was messing with NRF and listening for button presses to sleep/wake BLE. And I did have "save on send" enabled by accident. I also did a lot of hardware reset, reset(), save() and E.setBootCode() (roughly in that order) to try to fix things, but apparently I broke things even more :/

The peek functions return the same as the others here, and the erasePage calls solved it.