(cache)USB stick refuses to leave read-only mode. How to make it writable again?

TenTenths · 10-10-2025, 10:25 AM

Quote:

Originally Posted by onebuck

As one should consider a write protect switch is a potential failure point. Firmware/software level write protect is flexible plus a secure means to protect.

Totally in agreement, to be honest I don't think any of my current SD cards have a physical switch.

onebuck · 10-10-2025, 10:41 AM

Hi,
Some of my camera SD do have a physical switch.

TenTenths · 10-10-2025, 10:59 AM

Quote:

Originally Posted by onebuck

Hi,
Some of my camera SD so have a physical switch.

Damn, you got me second guessing myself so I had to check and turns out my Lexar cards ALSO have physical switches!

onebuck · 10-10-2025, 11:52 AM

Hi,

Personally with the OP's situation. I would myself just attempt a creation from the protected USB Flash to another known good Flash and put the protected/RO in a safe place if needed in the future. Flash drives are not as expensive as in the past. Even if one could/would recover to a write situation it would be a possible/potential failure use in the future. Not reliable thus not worth the time for me!

TenTenths · 10-10-2025, 12:19 PM

Quote:

Originally Posted by onebuck

Personally with the OP's situation. I would myself just attempt a creation from the protected USB Flash to another known good Flash and put the protected/RO in a safe place if needed in the future. Flash drives are not as expensive as in the past. Even if one could/would recover to a write situation it would be a possible/potential failure use in the future. Not reliable thus not worth the time for me!

Precisely my previous point, any USB or [micro]SD under 512Gb is really a commodity / consumable at this stage. Back it up and shred it, don't even bother storing it!

Quote:

Originally Posted by TenTenths

Sandisk will go read-only at the USB controller firmware level if it detects too many errors. Back stuff up and throw it in the bin or shred it.

JJJCR · 10-12-2025, 10:27 PM

Quote:

Originally Posted by onebuck

Hi,
Some of my camera SD do have a physical switch.

back in the day, was designing a card reader. my colleague told me that one of the pin should be left hanging since it has no use or no signal coming from the pin, when I took the project, it was actually the physical switch of the card. The signal is generated when the switch is manually triggered or else no signal can be seen.

exerceo · Today, 02:48 PM

Quote:

Originally Posted by sgosnell

I'm not familiar with that model. Dmesg says write protect is on. Is there a physical switch on the device? SD cards have a write-protect switch, but I don't know about that device. If there is no switch, the drive is possibly failing. Becoming read-only is a classic failure mode for flash drives.

Apologies for late response, I didn't notice it. No, the flash drive has no read-only switch.

Pretty much full-sized (non-micro) SD cards have a read-only switch, but it doesn't change anything inside the SD card. It only tells the card reader to deny write access.

The card reader has the final authority. Some card readers do not detect the write protection switch. But from my experience, almost all internal card readers in laptops and digital cameras respect write protection.

Quote:

Originally Posted by TenTenths

Sandisk will go read-only at the USB controller firmware level if it detects too many errors. Back stuff up and throw it in the bin or shred it.

No, I am keeping it. Why destroy a free backup copy of that data? It's not like I rely on it (the data is already backed up elsewhere), but it is better than nothing. Also, I am finding out for how much longer it remains readable and how it will report read errors. No read errors so far.

Unlike SanDisk, some low-end USB manufacturers like Alcor will return damaged data without reporting it as such, in which case the only way to locate damaged data is by noticing slowdowns in transfer rate of non-cached data.