My unit would not let me update to 1.2.5 from 1.2.4, no clue why. It just showed <invalid> in the updater.
- Download from Dell: https://www.dell.com/support/home/en-us/product-support/product/wyse-3040-thin-client/drivers
- Unzip it if it is zipped.
- Copy to a USB flash drive, FAT32 formatted.
- Boot the with F12 key.
- Follow instructions on screen.