Thank you very much pab567!
But I can not get the system to detect the firmware. I tried 3 different USB memory sticks. 8GB, 16GB and 128GB. I formatted them on Windows and on Mac as FAT32. I unpacked and placed the content in root on the drive. I tried updating from the Menu > Settings > System menu but also by holding the Menu button for 5 seconds. Bolero does detect the USB stick but absolutely not the firmware. The "select source" menu is all greyed out - CD ROM, USB Memory and SD Card. It's a Skoda Fabia so there is no CDROM or SD Card.. just a USB connection. I have updated this Bolero once before in 2020. It worked fine back then. Before it was on version 353 and I updated to 367. The update that I can't get to work is the 369. Is there a bug in 367 that prevents from detecting firmware on USB?