USB memory stick presents as two storage devices

Question

I have a USB memory stick that, when inserted into a computer, appears as two devices. The first is a CD-ROM drive and the second is a normal USB mass storage device.

dmesg gives the following:

[35325.116114] usb 1-2: new full speed USB device using ohci_hcd and address 7

[35325.868988] usbcore: registered new interface driver uas
[35325.875607] Initializing USB Mass Storage driver...
[35325.875675] scsi3 : usb-storage 1-2:1.0
[35325.876380] usbcore: registered new interface driver usb-storage
[35325.876382] USB Mass Storage support registered.
[35327.089961] scsi 3:0:0:0: CD-ROM            USB      Flash Disk       3000 PQ: 0 ANSI: 2
[35327.099399] scsi 3:0:0:1: Direct-Access     USB      Flash Disk       3000 PQ: 0 ANSI: 0 CCS
[35327.130825] sr1: scsi3-mmc drive: 0x/0x caddy
[35327.130956] sr 3:0:0:0: Attached scsi CD-ROM sr1
[35327.131047] sr 3:0:0:0: Attached scsi generic sg2 type 5
[35327.131205] sd 3:0:0:1: Attached scsi generic sg3 type 0
[35327.168612] sd 3:0:0:1: [sdb] 3905536 512-byte logical blocks: (1.99 GB/1.86 GiB)
[35327.182318] sd 3:0:0:1: [sdb] Write Protect is off
[35327.182322] sd 3:0:0:1: [sdb] Mode Sense: 43 00 00 00
[35327.223709] sd 3:0:0:1: [sdb] No Caching mode page present
[35327.223723] sd 3:0:0:1: [sdb] Assuming drive cache: write through
[35327.308129] sd 3:0:0:1: [sdb] No Caching mode page present
[35327.308133] sd 3:0:0:1: [sdb] Assuming drive cache: write through
[35327.336280]  sdb: sdb1
[35327.443196] sd 3:0:0:1: [sdb] No Caching mode page present
[35327.443201] sd 3:0:0:1: [sdb] Assuming drive cache: write through
[35327.443204] sd 3:0:0:1: [sdb] Attached SCSI disk
[35331.073317] UDF-fs: Partition marked readonly; forcing readonly mount
[35331.083014] UDF-fs INFO UDF: Mounting volume 'Tervetuloa', timestamp 2010/06/16 17:10 (10b4)

The memory stick seems to work like a U3 smart drive, but U3_tool won't recognize it.

What is this memory stick, and how do I remove and/or modify files on the CD drive?

Answer 1

Some USB sticks can be configured to present themselves as two or three storage devices. This works at firmware level – instead of a single disk with partitions, the OS sees two or three separate devices, so you cannot just repartition it.

(U3 is just one example. Another manufacturer, the name of which I forget, sells USB sticks with a ~200 MB read-only partition holding ~20 MB of promo JPEGs and Kaspersky trialware.)

You need special software to reconfigure the drive. Unfortunately, most such programs are Windows-only, not officially available to the public, and you have to know the flash controller being used inside your USB stick and find the specific program.

• Tools for U3 drives are widely available.
• UT165 – I have used this myself to remove the aforementioned Kaspersky junkware, seems like a common controller type.
• iCreate

^{if anyone has programs for other types, feel free to add.}

Answer 2

I have already seen several devices of this kind, and I have been unable to modify the partitions in order to end up having just an ordinary storage device.

I'm afraid that the manufacturer makes these configurations at hardware / firmware level and these can not be undone, at least in a ordinary way.

Answer 3

Can you repartition the memory stick? That's how U3 works. It keeps the U3 data on one partition, and your data on another. You might also try using Sandisks U3 Removal Tool. I think that's what I did.