> My dream is to intercept the write-enable lines on the flash chips holding these firmwares so I can lock out updates. And schedule a daily reboot for any memory-resident-only crap.
There was an open hardware project for SD card emulation, where the emulator could reject writes, https://github.com/racklet/meeting-notes/blob/main/community...
OSS emulation for SPI flash, https://trmm.net/Spispy/
Some USB drives (Kanguru) and SSD enclosures (ElecGear M.2 2230 NVME) have firmware and physical switch to block writes, useful to boot custom "live ISOs" that run from RAM.