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Topic: USB Flash Drive gets recognized as two block devices (Read 949 times) previous topic - next topic
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USB Flash Drive gets recognized as two block devices

So I was searching through some old flash drives, plugged one in, and saw this:
Code: [Select]
NAME   MAJ:MIN RM   SIZE RO TYPE MOUNTPOINTS
sdb      8:16   1   3.7G  0 disk 
sdc      8:32   1  78.2M  1 disk 
└─sdc1   8:33   1  78.2M  1 part
I verified that these two block devices belonged to the same device by unplugging the USB drive and both of them disappeared, and also the fact that fdisk showed "Disk model: Flash Disk" for both block devices.      

/dev/sdb is writable, however /dev/sdc and its partition is read-only.

I tried mount -o rw /dev/sdc1, but it still was read-only, so I'm guessing the firmware is forcing it to be read-only.

I checked /dev/sdc1, and it seemed to contain advertisements for a hotel in Berlin.

Is it possible to somehow make these two block devices show up as one, either by some tool or firmware level hackery?

Re: USB Flash Drive gets recognized as two block devices

Reply #1 –
These were normally produced with an autoplay on the RO part. So when plugged into a Windows PC an advertisement pops up.
Given away as freebies.

If it's one of these you may be able to remove it ? https://en.wikipedia.org/wiki/U3_(software)

Re: USB Flash Drive gets recognized as two block devices

Reply #2 –
Quote from: gripped – on
These were normally produced with an autoplay on the RO part. So when plugged into a Windows PC an advertisement pops up.
Given away as freebies.

If it's one of these you may be able to remove it ? https://en.wikipedia.org/wiki/U3_(software)
Thanks, I didn't know such software even existed.

Unfortunately I checked and found no signs of U3 software on the read-only partition, there wasn't any .exe files on it.

Re: USB Flash Drive gets recognized as two block devices

Reply #3 –
Gparted -> device -> Create partition table

Should nuke it
Cat Herders of Linux
 

Re: USB Flash Drive gets recognized as two block devices

Reply #5 –
Quote from: Lancia – on
Ah yes, classic cat herders of linux behaviour: I did not bother reading the post
Is it possible to somehow make these two block devices show up as one, either by some tool or firmware level hackery?

gparted -> device -> Create partition table

presto one device
Cat Herders of Linux

Re: USB Flash Drive gets recognized as two block devices

Reply #6 –
Quote from: cat herders of linux – on
Is it possible to somehow make these two block devices show up as one, either by some tool or firmware level hackery?

gparted -> device -> Create partition table

presto one device
You didn't understand what I said.

The two block devices you're referring to are in actuality two partitions of the same block device.

My problem is that /dev/sdb and /dev/sdc are completely different block devices that have no relation to eachother, what you do to one will not affect the other and vice versa, yet they both somehow exist on the same USB flash drive, this is why I say this must be the work of the firmware.

Re: USB Flash Drive gets recognized as two block devices

Reply #7 –
Quote from: cat herders of linux – on
Is it possible to somehow make these two block devices show up as one, either by some tool or firmware level hackery?

gparted -> device -> Create partition table

presto one device
In this context device = block device.
So all you can do with your solution is create a new partition on each block device this USB stick contains.

And 'presto' you still have two block devices.

You do a disservice to this forum posting technical advice on topics you seem not to have a grasp of the basics of yourself.
What worries me is that those that can instantly see this will be fine and mainly just ignore it and move on. But at some point you are going to cause damage to a less knowledgeable users install.

A while ago you mentioned being banned at multiple forums, with endeavouros being one of them. https://forum.artixlinux.org/index.php/topic,1081.msg25317.html#msg25317
You couldn't recall why.

I could hazard a guess !

Re: USB Flash Drive gets recognized as two block devices

Reply #8 –
Quote from: gripped – on
In this context device = block device.
So all you can do with your solution is create a new partition on each block device this USB stick contains.

And 'presto' you still have two block devices.

You do a disservice to this forum posting technical advice on topics you seem not to have a grasp of the basics of yourself.
What worries me is that those that can instantly see this will be fine and mainly just ignore it and move on. But at some point you are going to cause damage to a less knowledgeable users install.

A while ago you mentioned being banned at multiple forums, with endeavouros being one of them. https://forum.artixlinux.org/index.php/topic,1081.msg25317.html#msg25317
You couldn't recall why.

I could hazard a guess !

Oh no!  You hurt my widdle feeling!
Cat Herders of Linux

Re: USB Flash Drive gets recognized as two block devices

Reply #9 –
Quote from: Lancia – on
You didn't understand what I said.

The two block devices you're referring to are in actuality two partitions of the same block device.

My problem is that /dev/sdb and /dev/sdc are completely different block devices that have no relation to eachother, what you do to one will not affect the other and vice versa, yet they both somehow exist on the same USB flash drive, this is why I say this must be the work of the firmware.



https://www.ventoy.net/en/index.html

This program on Linux creates two block devices on the same device, one read only the other writable.   Maybe they could give you some Insight
Cat Herders of Linux

Re: USB Flash Drive gets recognized as two block devices

Reply #10 –
Quote from: gripped – on
In this context device = block device.
You do a disservice to this forum posting technical advice on topics you seem not to have a grasp of the basics of yourself.
What worries me is that those that can instantly see this will be fine and mainly just ignore it and move on. But at some point you are going to cause damage to a less knowledgeable users install.

Well thank goodness someone else agress with me, aside from the bad advice he gives, I would also add "elitism" to the list.

Quote from: cat herders of linux – on
Oh no!  You hurt my widdle feeling!

Good, so you agree that you're an incompetent person that shouldn't be listened to?

Quote from: cat herders of linux – on

https://www.ventoy.net/en/index.html

This program on Linux creates two block devices on the same device, one read only the other writable.   Maybe they could give you some Insight

Again, its the same thing, those two block devices are still partitions belonging to a single block device.

Re: USB Flash Drive gets recognized as two block devices

Reply #11 –
From what I could get:
1) Wiping and formatting the stick won't solve it. It's just going to let you set a writable partition on /dev/sdc/: https://askubuntu.com/questions/674142/usb-showing-2-devices-when-1-connected
2) If it's u3, there's (apparently) a tool that will let you get rid of it on Linux: https://unix.stackexchange.com/questions/624000/usb-flash-drive-showing-up-as-two-devices-not-two-partitions-on-linux
The post doesn't say where to get it and neither the repos nor the aur seems to have it, but I believe it's this one: http://u3-tool.sourceforge.net/
3) Maybe the stick it's designed that way and it's impossible to change it: https://bbs.archlinux.org/viewtopic.php?pid=1273160#p1273160 and https://superuser.com/a/1519807
Sorry if this doesn't solve your problem but all the others attempts I found got stalled.

Re: USB Flash Drive gets recognized as two block devices

Reply #12 –
Quote from: garza – on
From what I could get:
1) Wiping and formatting the stick won't solve it. It's just going to let you set a writable partition on /dev/sdc/: https://askubuntu.com/questions/674142/usb-showing-2-devices-when-1-connected
2) If it's u3, there's (apparently) a tool that will let you get rid of it on Linux: https://unix.stackexchange.com/questions/624000/usb-flash-drive-showing-up-as-two-devices-not-two-partitions-on-linux
The post doesn't say where to get it and neither the repos nor the aur seems to have it, but I believe it's this one: http://u3-tool.sourceforge.net/
3) Maybe the stick it's designed that way and it's impossible to change it: https://bbs.archlinux.org/viewtopic.php?pid=1273160#p1273160 and https://superuser.com/a/1519807
Sorry if this doesn't solve your problem but all the others attempts I found got stalled.
>>Sorry if this doesn't solve your problem but all the others attempts I found got stalled.

Oh no thank you very much, especially that Arch post gave me a better understanding:
Quote
BTW, it is not uncommon for USB devices to provide multiple interfaces.  This is true of both compound and composite USB devices.  http://en.wikipedia.org/wiki/Universal_ … tem_design

Essentially, one can pack multiple logic devices with separate interfaces onto one logical device.  SanDisk did this a lot where the would have one interface present itself as a CD ROM, and another as a mass storage device.  When you plugged it into a system running a popular operating system from the US Pacific Northwest, that OS would happily mount and autorun the CD interface allowing the installation of drivers and toolbar gadgets.

I guess the only way is to flash the firmware.