Raspberry Pi Forums

I student might bring a microSD/SD-card that is overclocked beyond warranty. How do you prevent that? I think it is an advantage that there is no internal flash-memory on the Raspberry Pi, because there can be nothing causing problems when switching SD-cards.

you don't allow students to swap SDcards.

it's the only way

mob-i-l wrote:I student might bring a microSD/SD-card that is overclocked beyond warranty. How do you prevent that? I think it is an advantage that there is no internal flash-memory on the Raspberry Pi, because there can be nothing causing problems when switching SD-cards.

It's an interesting point, and difficult to police.

However, the likelihood of breaking an overclocked Pi is pretty remote. In the vast majority of cases, the Pi simply won't boot, and returning to standard settings will mean it will recover. But as you say, the warrantee bit would be set, even if the Pi is still 'ok'. I'm not familiar with any cases of a Pi actually being broken by overclocking, except in some rather extreme cases that require more than just changes to the SD card.

So while it is of concern, I'm not sure how much of a concern it is.

The idea was mooted of a config.txt option that would set an OTP bit to prevent that Pi from ever honouring dangerous overclock settings. I see reference to "never_over_voltage" in start.elf, but I do not know if that is the same thing, or if it is implemented, and it would difficult to test.

How do I check if the warranty bit is set on a Raspberry Pi 2 B?

FWIW, I think it was held, in the early discussions of over-clocking/over-volting (way back when, in the early days of the Pi) that you couldn't break anything on the board by over-clocking - that is, you could only break it by over-volting. Is that still the consensus?

Note to nit-pickers: Of course, you can wreck your SD card via over-clocking. What I said above is "can't break anything on the board".

jojopi wrote:The idea was mooted of a config.txt option that would set an OTP bit to prevent that Pi from ever honouring dangerous overclock settings. I see reference to "never_over_voltage" in start.elf, but I do not know if that is the same thing, or if it is implemented, and it would difficult to test.

I don't see that that would be much of a help if someone swapped SD cards.

W. H. Heydt wrote:

jojopi wrote:The idea was mooted of a config.txt option that would set an OTP bit to prevent that Pi from ever honouring dangerous overclock settings. I see reference to "never_over_voltage" in start.elf, but I do not know if that is the same thing, or if it is implemented, and it would difficult to test.

I don't see that that would be much of a help if someone swapped SD cards.

I think the point is that that option would permanently set a flag on the Pi which could be detected by the firmware and tell it to ignore any over voltage settings in config.txt.

Because the flag is permanent in the Pi it wouldn't matter if the card were swapped for another.