USB not recognized in 3850

[Kn1ghtR1d3rOfD00m]

Hi all, 

Im trying to transfer a IOS image to upgrade a 3850 switch, as soon as I put the USB drive to the front of the switch, I go to the CLI and run the command: show usb-devices summary (it is the only command available) and it shows and display the name and even the serial of the USB, 

however, if I want to see the files (IOS image file) inside the USB, with the command show usbflash0:/ it does not show anything, 

I tried to search for answer on the forum but no like this one, and a lot of post states that with the command: dir usbflash0:/ will display but this command is not available, 

is there a command to active a usbflash0:/ slot ?

I even tried formatting the drive to FAT32 and NTFS but still the same results, 

Am I missing something? 

the current switch IOS image is: 

Cisco IOS Software [Denali], Catalyst L3 Switch Software (CAT3K_CAA-UNIVERSALK9-M), Version 16.3.1, RELEASE SOFTWARE (fc3)

Switch Ports Model              SW Version        SW Image              Mode

------ ----- -----              ----------        ----------            ----

*    1 32    WS-C3850-24S       16.3.1            CAT3K_CAA-UNIVERSALK9 INSTALL

Regards, 

[Reza Sharifi · Accepted solution]

Hi,

Not all USB drives work with Cisco devices.  Try using another USB from a different vendor.

Sometime you have to try 2 or 3 different vendors.

HTH

[Kn1ghtR1d3rOfD00m]

Ok, thanks, 

Im preparing 3 USB devices  my concern was because somehow the usb is recongnized because it displayed its information, but the CLI command is not what most people say, its like the version of IOS currently running does not even has the show usbflash0:/ cause even if there is not USB driver, at least I should get an error, 

Let me try 3 more, I will give you updates, thanks

[Kn1ghtR1d3rOfD00m]

Hi 

I tried with a Cisco USB :)  and it worked, yeah,

thanks

[joseperezctr]

THANKS for the suggestion!  I tried 2 different USB thumb drive and the second one worked (an old 1gig drive which I formatted it FAT16).

[carlosgfranco · Accepted solution]

For anyone else out there having this issue: The drive needs be formatted as FAT (a.k.a FAT16).

FAT can only be used on MBR partitions of up to 4GB so if you have a flashdrive larger than that you'll need to use diskpart (or your preferred partition software) to create a 4GB partition. Then you will be able to format that partition as FAT and the router will recognise it.

Cheers!

EDIT: Adding the diskpart commands.
EDIT2: Updating to consider newer GUID partition tables, so adding a command to convert it first to MBR. Major thanks to the people that highlighted this!

THIS WILL WIPE THE CONTENTS OF YOUR USB PENDRIVE:

diskpart
list disk
select disk <INDEX OF USB DISK>
clean
convert mbr
create part primary size=4000
active

Done! Now you can use Windows Explorer to format the drive as FAT.

[brunopereira81]

This should be actually the correct answer! Thanks!

[thura26687]

Thanks it is working.

---

@carlosgfranco wrote:

For anyone else out there having this issue: The drive needs to be formatted as FAT (a.k.a FAT16).

FAT can only be used on partitions of up to 4GB so if you have a flashdrive larger than that, you'll need to use diskpart (or your preferred partition software) to create a 4GB partition. Then you will be able to format that partition as FAT and the router will recognise it.

Cheers!

EDIT: Adding the diskpart commands. THIS WILL WIPE THE CONTENTS OF YOUR USB PENDRIVE:

diskpart
list disk
select disk <INDEX OF USB DISK>
clean
create part primary size=4000
active

Done! Now you can use Windows Explorer to format the drive as FAT.

---

[murphs76]

This worked for me except for the part "create part primary size=4000". I tried different sizes until it to worked.

create part primary size=3900

create part primary size=3800

create part primary size=3700

The "create part primary size=3700" worked for me and now I can use it for usbflash0:. The switch reports "3900440576 bytes total (3900440576 bytes free)".

[carlosgfranco]

hi @murphs76 , perhaps your usb drive was probably already 4GB or less? the instructions are for larger drives where you can't format as FAT16 becase Windows hides the option if the drive's partition(s) are over 4GB. please let me know if this was the case just to confirm. glad to know that -with some tweaking- it worked.

[sayednabhan]

worked

[sabi4evr]

Thanks bro.

this saved my life

followed the exact steps. had to convert the disk to MBR. I used a 8 GB drive. But was unable to initialize in Win 10, could be due to the disk type (FAT 32). The Cisco was able to see the USB after this process.

thanks a bunch

[rmrf2020]

this literally saved my life. NO ONE is mentioning you need to format drive to MBR in addition to FAT32 format. 

AND NO YOU DON'T NEED A CISCO USB. ANY WILL WORK! usb 2.0 or 3.0. Spent hours on such a minor thing!!!

[szaleski]

Thank you for this post. I was able to utilize this on a WD My Passport 1TB USB hard drive. This was able to register on Cisco 3650s, 3850s, and 9300s. I can still use the rest of the drive in NTFS and keep the IOS versions and configs on the NTFS portion, then transfer what I need back and forth between the NTFS and FAT partitions. Appreciate the help!!

[Mosasa]

THANKS !!!