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

exerceo · 10-05-2025, 02:46 PM

dmesg:

Code:

[2304237.356095] scsi 5:0:0:0: Direct-Access      USB      SanDisk 3.2Gen1 1.00 PQ: 0 ANSI: 6
[2304237.356396] sd 5:0:0:0: Attached scsi generic sg4 type 0
[2304237.356778] sd 5:0:0:0: [sdd] 60063744 512-byte logical blocks: (30.8 GB/28.6 GiB)
[2304237.359283] sd 5:0:0:0: [sdd] Write Protect is on
[2304237.359287] sd 5:0:0:0: [sdd] Mode Sense: 43 00 80 00
[2304237.359617] sd 5:0:0:0: [sdd] Write cache: disabled, read cache: enabled, doesn't support DPO or FUA

hdparm:

Code:

# hdparm -r0 /dev/sdd

/dev/sdd:
 setting readonly to 0 (off)
 readonly      =  1 (on)

It's a SanDisk Ultra USB stick. It's fully readable and no data is corrupted.

It is also write-protected on a different computer, so the issue is with the USB stick.

If there is no way to get it writing again, it's not that big of a loss, but it would be nice to have it working again.

sgosnell · 10-05-2025, 03:16 PM

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.

teckk · 10-05-2025, 03:44 PM

How about this:
https://askubuntu.com/questions/1016...protection-off

JJJCR · 10-05-2025, 08:33 PM

Quote:

Originally Posted by exerceo

dmesg:

Code:

[2304237.356095] scsi 5:0:0:0: Direct-Access      USB      SanDisk 3.2Gen1 1.00 PQ: 0 ANSI: 6
[2304237.356396] sd 5:0:0:0: Attached scsi generic sg4 type 0
[2304237.356778] sd 5:0:0:0: [sdd] 60063744 512-byte logical blocks: (30.8 GB/28.6 GiB)
[2304237.359283] sd 5:0:0:0: [sdd] Write Protect is on
[2304237.359287] sd 5:0:0:0: [sdd] Mode Sense: 43 00 80 00
[2304237.359617] sd 5:0:0:0: [sdd] Write cache: disabled, read cache: enabled, doesn't support DPO or FUA

hdparm:

Code:

# hdparm -r0 /dev/sdd

/dev/sdd:
 setting readonly to 0 (off)
 readonly      =  1 (on)

It's a SanDisk Ultra USB stick. It's fully readable and no data is corrupted.

It is also write-protected on a different computer, so the issue is with the USB stick.

If there is no way to get it writing again, it's not that big of a loss, but it would be nice to have it working again.

some usb stick, got a slide switch to make the USB read only. I am not sure whether that USB stick got one, check on it.

or try:
sudo mount -o remount,rw /dev/sdd /mnt/usbpoint

colorpurple21859 · 10-06-2025, 10:00 AM

Is the partition table something other than msdos or gpt?

DavidMcCann · 10-06-2025, 11:02 AM

Linux makes usb sticks read-only when the filing system seems to be corrupt to prevent you making it even worse.

The first step is to use fsck to see if it will clean up the device. If that works, you are probably OK.

If fsck doesn't work, or if the device gives trouble again in the future, you need to save the contents and reformat it. Gparted should work, but if it won't, you may still be able to rescue the thing. Unmount, after noting its /dev name, and run this command after which gparted should work.

Code:

dd if=/dev/zero bs=1M count=10 of=/dev/whatever

If you have further trouble, then the only solution is replacement

exerceo · Today, 04:51 PM

Quote:

Originally Posted by JJJCR

some usb stick, got a slide switch to make the USB read only. I am not sure whether that USB stick got one, check on it.

A physical switch?

Quote:

or try:
sudo mount -o remount,rw /dev/sdd /mnt/usbpoint

Doesn't work. It seems to be on a hardware level.

Quote:

Originally Posted by DavidMcCann

If you have further trouble, then the only solution is replacement

I did some research and my closest guess would be that firmware of the USB stick refuses to write any more because it reached its end of life, as suggested by this post by AnthonyNYC from the now defunct CNET forum.

I used it as for a portable Linux installation for some time, so it might have been exposed to workloads it wasn't designed for. But it still reads at solid 140 MB/s, which is close to its advertised speed of 150 MB/s. And it never had corrupted data. But it shouldn't anyway, because that's expected from a reputable brand. Maybe SanDisks's firmware is "over-cautious" and pre-emptively write-protected it.