Flash drive weirdness

pcalvert · 2025-10-22 08:38:14

I recently purchased some USB flash drives in order to create bootable installation drives and a portable installation of Devuan. I was checking them out last night and noticed something that (to me) seems a bit strange.

This is for a "128 GB" USB flash drive:

# fdisk -l /dev/sdb
Disk /dev/sdb: 115.43 GiB, 123941683200 bytes, 242073600 sectors
Disk model: USB DISK 3.0    
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0xc1a97bb4

Device     Boot Start       End   Sectors   Size Id Type
/dev/sdb1       97664 242073599 241975936 115.4G  c W95 FAT32 (LBA)

And this is for a "32 GB" USB flash drive:

# fdisk -l /dev/sdb
Disk /dev/sdb: 28.91 GiB, 31037849600 bytes, 60620800 sectors
Disk model: USB Flash Drive 
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0x1e67b218

Device     Boot Start      End  Sectors  Size Id Type
/dev/sdb1  *       64 60620799 60620736 28.9G  c W95 FAT32 (LBA)

Of the two, the 128 GB drive is the one that looks weird to me. Notice where the partition starts. I've never before seen a flash drive with that much "empty" space before the first partition. Does anyone have any idea of what's going on, or might be going on, with this drive?

Altoid · 2025-10-22 11:11:25

Hello:

pcalvert wrote:

... 128 GB drive is the one ...

Is this how it came 'out-of-the-box' or did you format it?

You may want to run a read-only check on it with dosfsck and/or have a look at it with the gnome-disk-utility
It shows things that Gparted will not.

Best,

A.

pcalvert · 2025-10-22 11:38:19

Altoid wrote:

Is this how it came 'out-of-the-box' or did you format it?

The drive came that way. All I did was run that fdisk command and mount the partition to see if the drive came with any documents or software (it didn't).

Altoid · 2025-10-22 12:18:38

Hello:

pcalvert wrote:

... came that way.

I see.
I assume it came in a sealed blister package without any indication of use.

I have never seen a USB drive with what you see in your fdisk printout but one never knows.
I have read that memory prices are surging lately, mainly due to dwindling stocks and foundry production having reached their limit.

It would be interesting to know the brand/model of your USBs.

It may well be that (for whatever commercial reason) the chip in the 128Gb drive is a higher capacity (eg: 256Gb or higher) but with the firmware blocking access to those sectors due to it being sold at 128Gb prices or because it is damaged and instead of binning it, the OEM decided to sell it as a 128Gb device.

That said, the only (?) answer to your OP may lie in checking the drive as suggested.
ie: a read-only check on it with dosfsck and looking at what the gnome-disk-utility says about it.

You may also want to check read/write speeds with the gnome-disk-utility, I had a nasty surprise from Kingston some time ago.
If interested see here: https://dev1galaxy.org/viewtopic.php?id=7264

Whatever the result, do let us know what you find out.

Best,

A.

pcalvert · 2025-10-22 13:04:59

Altoid wrote:

I assume it came in a sealed blister package without any indication of use.

Yes.

Altoid wrote:

It would be interesting to know the brand/model of your USBs.

The 128 GB flash drive is a Silicon Power Blaze B02, and the 32 GB flash drive is a Lexar JumpDrive V100. By the way, the Lexar drive came in a pack of three, and one of the three is clearly defective (much slower than the other two).

rolfie · 2025-10-22 13:08:26

A check if the memory on the stick really is the advertized one can be done with the f3 utility.

The first thing I do with any USB stick I buy.

Last edited by rolfie (2025-10-22 13:43:38)

stargate-sg1-cheyenne-mtn · 2025-10-22 14:05:06

these might be of some value:

https://www.theregister.com/2024/02/07/failed_usb_sticks

https://arstechnica.com/gadgets/2024/02/rejected-chips-hidden-microsd-cards-plague-the-usb-stick-market/

https://forum.tinycorelinux.net/index.php/topic,26762.0.html

https://forum.tinycorelinux.net/index.php/topic,26778.0.html

.

pcalvert · 2025-10-22 14:25:13

rolfie wrote:

A check if the memory on the stick really is the advertized one can be done with the f3 utility.

Yes, I did that for the three Lexar drives. I didn't do that for the Silicon Power drive because I didn't have time, but I will. However, that is not my main concern. At this point, I am mainly concerned about the "weirdness" of the Silicon Power drive.

I consider all "foreign" (new to me) flash drives as potentially hostile hardware. Because of that, the unusually large amount of "empty" space before the first (and only) partition of the Silicon Power drive is concerning. Could there be malicious code hiding in there?

Since I was planning on doing it anyway, I am going to go ahead and wipe the drive. I will then format it and use f3 and flashbench to conduct some tests on the drive. Oh, and as a precaution, before doing that I will use dd to back up the MBR and partition table in case I need (or want) to restore them for some reason.

fsmithred · 2025-10-22 16:52:43

Look at the whole device in hexedit to see if there's any code at the beginning. I don't have any usb stick that I haven't re-partitioned to tell you what it should look like. Maybe image the image it with dd if you want to examine it later.

I think I may have seen similar on a 128 or 256G and didn't think much about it before I re-partitioned. Or I could be imagining it. FWIW, my 128 and 256G sticks suck compared to 32. They're s - l - o - w.

I read about micro-sd cards hidden inside usb sticks. Last time I looked at them in the store, they had combo packs with "USB and micro-sd". They no longer hide the micro-sd - they let you insert it into the usb housing yourself.

Calamity · 2025-10-22 18:11:41

I have a 64G TeamGroup drive that I use regularly, when I looked at it in Gparted I also saw a chunk of unallocated space at the beginning. It was quite small, but still noticeable, maybe about 20MB. I reformatted it to use all the space available, did not suffer any data loss so far but of course with such oddities going on it's best to keep backups everywhere you can... It's also supposed to be USB 3.0 but is very slow on writes. Flash memory is getting very sketchy, a lot of people complain, especially when it comes to bigger capacity drives/cards.

Got another 64G drive by Kingston (bought together with the first one), that one came preformatted as FAT32 instead of ExFAT for some reason... Strange.

Here is another good page on the subject of fake flash drives: https://rmprepusb.com/tutorials/007-all … sh-drives/ .

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#1 2025-10-22 08:38:14

Flash drive weirdness

#2 2025-10-22 11:11:25

Re: Flash drive weirdness

#3 2025-10-22 11:38:19

Re: Flash drive weirdness

#4 2025-10-22 12:18:38

Re: Flash drive weirdness

#5 2025-10-22 13:04:59

Re: Flash drive weirdness

#6 2025-10-22 13:08:26

Re: Flash drive weirdness

#7 2025-10-22 14:05:06

Re: Flash drive weirdness

#8 2025-10-22 14:25:13

Re: Flash drive weirdness

#9 2025-10-22 16:52:43

Re: Flash drive weirdness

#10 2025-10-22 18:11:41

Re: Flash drive weirdness

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