USB stick seen as two devices

lucak3 · 2011-07-30 09:40:08

Hi everyone, i just got this flash device and plugging it in, i noticed it spawned two devices: i normalli have sda*, which is my internal hdd, with this stick in i get sdb and sdc. Not just two partition, two devices! I tried it on a Win box, and it seems to only recognize the first device (sdb). This is a problem, because on this one space is a lil 1MB... Consider that this stick is 4GB, that seems to be almost all on the second.

Relevant dmesg output:

[  362.230019] usb 1-4: new high speed USB device number 2 using ehci_hcd
[  362.714663] usbcore: registered new interface driver uas
[  362.735340] Initializing USB Mass Storage driver...
[  362.735508] scsi6 : usb-storage 1-4:1.0
[  362.736053] usbcore: registered new interface driver usb-storage
[  362.736057] USB Mass Storage support registered.
[  363.769570] scsi 6:0:0:0: Direct-Access              USB DISK Pro     PMAP PQ: 0 ANSI: 6
[  363.769861] sd 6:0:0:0: Attached scsi generic sg2 type 0
[  364.902079] scsi 6:0:0:1: Direct-Access              USB DISK Pro     PMAP PQ: 0 ANSI: 6
[  364.902359] sd 6:0:0:1: Attached scsi generic sg3 type 0
[  364.905432] sd 6:0:0:0: [sdb] 2048 512-byte logical blocks: (1.04 MB/1.00 MiB)
[  364.906166] sd 6:0:0:0: [sdb] Write Protect is off
[  364.906170] sd 6:0:0:0: [sdb] Mode Sense: 23 00 00 00
[  364.906173] sd 6:0:0:0: [sdb] Assuming drive cache: write through
[  364.906999] sd 6:0:0:1: [sdc] 7809024 512-byte logical blocks: (3.99 GB/3.72 GiB)
[  364.909452] sd 6:0:0:1: [sdc] Write Protect is off
[  364.909457] sd 6:0:0:1: [sdc] Mode Sense: 23 00 00 00
[  364.909459] sd 6:0:0:1: [sdc] Assuming drive cache: write through
[  364.912280] sd 6:0:0:0: [sdb] Assuming drive cache: write through
[  364.942432]  sdb: unknown partition table
[  364.944177] sd 6:0:0:1: [sdc] Assuming drive cache: write through
[  364.946112]  sdc: sdc1
[  364.948283] sd 6:0:0:0: [sdb] Assuming drive cache: write through
[  364.948288] sd 6:0:0:0: [sdb] Attached SCSI removable disk
[  364.948782] sd 6:0:0:1: [sdc] Assuming drive cache: write through
[  364.948786] sd 6:0:0:1: [sdc] Attached SCSI removable disk

Here the question: is it possible to make it so that there is only one device?

rwd · 2011-07-30 11:56:24

My guess it is some kind of windows encryption feature on the drive. Have you tried dd-ing and reformatting ?

brebs · 2011-07-30 11:59:46

Tell udev to ignore it, with a rule in /etc/udev/rules.d/ such as:

KERNEL=="sd*", ATTRS{serial}=="07140A5D1CBB", ATTR{size}=="2880", OPTIONS="ignore_device"

lucak3 · 2011-07-30 12:05:52

I tried that to no avail: deleted all partitions, then 'dd if=/dev/zero of=/dev/sdb bs=1M count=5' reports that it could write just 1M, while if done on sdc it just works, but doesn't stop it from being seen as 2 devices, obviously i took it off then reinserted...

brebs wrote:

Tell udev to ignore it, with a rule in /etc/udev/rules.d/ such as:
KERNEL=="sd*", ATTRS{serial}=="07140A5D1CBB", ATTR{size}=="2880", OPTIONS="ignore_device"

That's not what i mean: it's a solution just for my pc, and even then, just for Linux.

Last edited by lucak3 (2011-07-30 12:08:38)

rwd · 2011-07-30 12:43:47

You could try re-flashing the firmware and/or return it to the shop.

brebs · 2011-07-30 12:44:15

Format the large drive/partition as FAT32, then Windows Explorer should show it.

Did it show in Windows' partition manager?

Are there any files in the 1mb partition? I would expect such a partition to contain the Windows drivers for the USB drive, needed by XP but not by Vista or later I would guess.

lucak3 · 2011-07-30 13:20:17

The large partition (that was in FAT32) was not showing on Windows, that's exactly the bigger part of the problem, else it would have been almost fine...
The slim partition was empty. I think the drive was not recognized as a stick, and that's why the bigger partition couldn't be shown.
Anyway, i'll try to format the large one and see if it works now on Win.

johnny_boy · 2013-05-15 10:18:58

I've got the same issue on a stick I formatted to a bootable Kubuntu 12.04 "liveCD". I wonder if it's EFI-related. Both Windows 8 and Kubuntu 13.04 don't allow me to delete all the partitions to create a new one.

ewaller · 2013-05-15 15:36:31

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.

wensveen · 2016-09-01 06:49:21

Old question, I hope to get to the bottom of this anyway.

ewaller wrote:

BTW, it is not uncommon for USB devices to provide multiple interfaces.

Is there any way to thwart this behavior so that it shows as only one device?

For now, I'm formatting the smaller partition as ext3 so only the larger FAT32 partition will show up on Windows.

Arch Linux

#1 2011-07-30 09:40:08

USB stick seen as two devices

#2 2011-07-30 11:56:24

Re: USB stick seen as two devices

#3 2011-07-30 11:59:46

Re: USB stick seen as two devices

#4 2011-07-30 12:05:52

Re: USB stick seen as two devices

#5 2011-07-30 12:43:47

Re: USB stick seen as two devices

#6 2011-07-30 12:44:15

Re: USB stick seen as two devices

#7 2011-07-30 13:20:17

Re: USB stick seen as two devices

#8 2013-05-15 10:18:58

Re: USB stick seen as two devices

#9 2013-05-15 15:36:31

Re: USB stick seen as two devices

#10 2016-09-01 06:49:21

Re: USB stick seen as two devices

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