For this test, I initially upgraded a Dell Wyse 3040 ThinClient with ThinOS to 9.0 with the Dell Wyse Management Suite 3.0. After my tests were finished, I wanted to use 8.6 on this device again, as I use it mainly to reconstruct customer issues, and most customers still use 8.6.
Go to http://downloads.dell.com/wyse/USBFT/ and download the latest Version of the Dell Wyse USB Imaging Tool, which is as of today version 3.3.0. You should also consider downloading and reading the User’s Guide.
Install the app on your Windows PC.
Next, you have to download the proper Merlin Image for your device not the raw image, in our case a Dell Wyse 3040: https://www.dell.com/support/home/de-de/product-support/product/wyse-3040-thin-client/drivers
Extract the ZIP files until you reach the .RSP file:
Now prepare a 2GB+ USB flash drive and format it with FAT32.
Next, start the USB Imaging Tool with Admin permissions. Select the correct USB-Drive and select Image Push mode in 64 bit. Press the + button at the bottom and select the WTOS_3040_8192_0.rsp file. Confirm your configuration and let the tool create the USB drive.
After the USB drive is created, eject it from Windows and plug it into your Dell Wyse 3040 with ThinOS 9.0.
Warning: Don’t use the blue front UBS 3.0 port, that didn’t work for me. Only the two back ports worked for me.
Start up the device and press F12 until you the pre-boot selection menu appears. Select the Device:
UEFI “YOUR USB STICK NAME/VENDOR”.
Hint: If the USB device does not appear in the boot menu, you may want to enter the BIOS settings and reset it to factory defaults.
The default BIOS password for Dell Wyse devices is: Fireport
You’ll now boot up the imaging menu and select the prepared 8.6_013 image, which will downgrade ThinOS from 9.0 to 8.6:
Press OK to start the process:
Wait until it’s finished:
After the process finished successful, remove the USB drive and press the restart button:
The setup will continue, finish and leave you with a Dell Wyse 3040 ThinOS version 8.6_013:
That’s it, feel free to ask questions and leave comments below, thank you!
Ps.: This method might also be useful, if you ever encounter a bricked device.