USB flash drive changes to read-only on the fly

[Franz Waldmüller]

Vaibhav Dalvi wrote:
> On Thu, Sep 23, 2010 at 3:21 AM, andrew clarke <mail at ozzmosis.com> wrote:
> 
>> On Wed 2010-09-22 22:21:27 UTC+0200, Daniel Louw (daniel at dline.co.za)
>> wrote:
>>
>>> This might be a silly question, but it is very frustrating.
>>>
>>> I have this memory stick, a 2 GB one formatted with FAT32.
>>>
>>> I was working on a .C file stored on the memory stick, saving as I
>>> made progress with the code. Then all of a sudden I cannot save
>>> anymore. I get an error saying the disk is read only. I cannot create
>>> new folders or files or anything. chmod doesn't work, it simply says
>>> read only partition. What the hell?
>>>
[snip]
> 
> More chances are that your fat32 FS got an error. Which means you don't have
> any other option than to copy the data else where and format it. It might be
> the reason that your pen drive's flash chip is failing. 
[snip]
I had some failing flash drives, too. Especially if you write data to 
them frequently. If you want to test the flash drive and not the 
filesystem, backup your data on another device and write with dd to the 
flash drive (CAUTION! This permanently deletes data, don't execute the 
following commands if you don't know them):

dd if=/dev/zero of=/dev/sdX
you will need to be root to access the drive directly. If the flash 
drive is failing you might get some In- and Output Errors. If you print 
the logfile you will have less troubles when asking for a replacement.

just my 2c
Franz