What would suddenly cause it to become damaged or corrupt?
Two words, cheap & nasty.
Could be caused by any number of reasons, poor quality B or C grade flash chips, buggy software, minimal or non-existent QC and testing during R&D and/or manufacturing. There's some very good reasons why a tablet like this only costs say $50-$60, and something like a Google Nexus or Samsung Tab can be well over $200. DOA is another frequent problem with cheapo tablets, as well as fluky malfunctioning WiFi.
I liken the cheapo tablets coming from China to the crappy transistor radios that flooded out of Hong Kong in the 60s and 70s. Most of them were rubbish and often didn't work very well, and had very short lives.
As the software is apparently corrupted, it's got to be re-flashed, good luck trying to find a ROM file....
Manufacturer: unknown
Bootloader: unknown
I've got a cheapo tablet myself that originated from some tech shop in Shenzhen, an Ampe. It frequently crashes, the screen is not much good, battery life is short, doesn't work properly with 3G/4G USB modems even though it's supposed to. I only use it to watch videos in bed, and sometimes to show ESL materials to my one-to-one students.