Can Flash controllers make a card readonly?
Yes! For SD Cards writing 1 to CSD Register's Bit 12 and 13 can enable write protection, permanent or temporary.




Regarding the Q&amp;A you have referenced over here. I am not sure or I can confirm but while working with SD Card's I read on some material that when SD card starts to detect that it's life cycle is getting over,It puts itself into Read Only mode so you dont put up your valuables over there and can read all the stuff that you have stored on it.

I have just READ, I haven't confirmed it because I don't remember the source neither have I tested it practically. So take it with a pinch of salt.