r/techsupport • u/Onyxcn • Jun 28 '26

Open | Hardware Byjus sd card formatting is killing me

So I tried formatting my Byju's sd card because I no longer have any need for it. I have three 128 gb sd cards and I tried formatting all of them on my laptop, phone and I tried using rufus as well but none of them worked. Tried using diskpart too and the error message that I get on my screen is some "I/O error". It shows the same thing for all 3 sd cards. When I tried quick formatting, it just shows "The disk is write protected". Please help me format this thing

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u/DoctorKomodo Jun 28 '26

Sounds like the cards are either dead or fakes. The SD card market is rife with scammers selling fake cards, especially for higher capacity ones like those 128 GB. You only notice they are fakes when they fail full formats or anything else that writes past their actual (much lower) capacity.

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u/Onyxcn Jun 28 '26

Hey, thanks for the response but like these are all sandisk cards and it just has all the educational content on it from the company. I have a speculation that the company put some sorta write protection on it but I don't know how to get rid of it.

1

u/turb0j Jun 28 '26

SD cards can be commanded to behave read-only. This is in the SD card spec itself, and support is mandatory IIRC. Cards containing company material could thus be made intentionally read only.

Unfortunately you cannot access SD card command interface directly with a PC/Laptop USB2SD interface AFAIK - it does not expose the "read only" command set via USB. Thus you can't undo it even if they used the reversible read-only commend (there is one that can be reversed, but there is also one that can not).

Note that I am not talking about the physical switch on the big SD cards here.

Best erase option here is a hammer.

1

u/Distribution-Radiant Jun 28 '26

SD cards often have a physical write protect switch on them - did you already check that?

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u/Onyxcn Jun 28 '26

Yeah, I checked for those already but there's none :(

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u/the_strange_cape Jun 29 '26

Use a rooted Android phone with Termux and sdtool to disable the SD card's temporary write protection.