Can it be unbricked?

I would see if the USB poet opn the Scout receiver supports data - that might be the way to do it based on preliminary guesses and the research I did on the monitor. Dexcom does have a app on their site to do it from a PC: https://www.dexcom.com/faqs/software-req...

I do see a reset button on the back when you open it, but without back removal, you can't access it unless the hole is recessed, BUT visible. I would start at the bottom and see if you can feel any round bumps closer to the bottom. If you can do that to at least reset it, then you might be able to get it into a recovery mode to update it. It might wipe out the sensor average readings if it's destrucive to both the firmware, RAM and NVRAM data but it shouldn't wipe out the serial number. For reference this is where I got my info from: https://device.report/dexcom/mt22949

Please take this with some caution, as it's an experienced guess from someone in IT and automotive specialties. I'm not diabetic (as in Type 1 or 2) where I need a Dexcom device, so I'm inferring from what I can see on the device, as Dexcom (of course) doesn't document a recovery procedure because they make more money on selling you a new one from insurance companies who will pay them handsomely, so there is no incentive. Dexcom usually replaces these if this happens, so if you feel the risk is too high, give them a call; otherwise, you might need to get insurance to buy you another one. Insurance probably will not want it back, but you might need a PA to replace it. Get a prick meter if your insurance is slow and you can't wait.