Download and install "u-center" version 20.06.01 or better from 
https://www.u-blox.com/en/product/u-center-windows

Start "u-center" (= "C:\Program Files (x86)\u-blox\u-center_vxx.xx.xx\u-Center.exe")

Connect the serial port via the "GPS PROG" adapter cable with the HSx box:
- Select "Receiver" > "Autobauding", or choose
  - "Receiver" > "Connection" > "COMx"
  - "Receiver" > "Baudrate" > "115'200" (or "38'400" if HSx is set to 38400 bd)

If the desired target baudrate is different from the current baudrate, select the desired target baudrate:
- Select "View" > "Configuration View" (Ctrl+F9)
- Select tree node "PRT (Ports)"
- Select desired target baudrate
- Press "Send" in the last line of the "Configure" window

Transmit the configuration file:
- "Tools" > "Receiver Configuration..."
- Select Generation: "u-blox Generation 9"
- Select the corresponding configuration file (*.TXT)
- Check checkbox "Store configuration into BBR/Flash (non-volatile memory)" if possible
- Press "Transfer file -> GNSS"
- [Press YES quickly if a confirmation messege box arises]

Save the configuration into Flash Memory (and Backup Battery ROM)
- Select "View" > "Configuration View" (Ctrl+F9)
- Select tree node "CFG (Configuration)"
- Press "Send" in the last line of the "Configure" window
