My understanding of flash is that it's an address-by-address basis... Like, the same location can't be written to more than X times... Other locations on the flash chip should still be fine.

Thats how I remember it as well, and this is why I believe the current state data is moved around quite a bit. I'm sure the exact number of spaces could be found in the kernel source. This in effect would then turn the real limit into 100,000 custom logo changes/upgrades before an issue arrises.