3 ms·

Have you ever used a Linux LiveCD? Or booted a machine off the network? The latter is a very common way to operate servers. In both cases you can write to the

• bjt2n3904 5y ago
  I've built a BusyBox image that TFTPs over to do the initial firmware flash, all ramdisk based. I've got physically write protected ICs on my boards. I almost rigged up my board to do write once NOR flash for U-boot. I know read only systems can be built, and everything else can be tmpfs. (And infact, I've built them.) People seem to be thinking I'm saying this is impossible. I'm not, I never did. I'm sorry I'm frustrated, but it's difficult to respond to things you didn't say. I'm saying, compared to a power cut switch for a webcam (which, I seem to remember even Apple screwed up accidently), a write protect switch is more challenging. A power cut switch is mostly challenging mechanically. How do I get the dang thing on the case? But otherwise, that's the only consideration. For a truly hardware based write protect switch that disables write capabilities at the silicon level, you have to adapt your image, your software, your hardware, and many of your procedures for the bring up process. Is that challenging? For some people in this thread, I suppose not. But compared with a power cut? Orders of magnitude more challenging. Especially when you are bringing this to a massive codebase that hasn't had this as a design consideration.