STMCubeProgrammer FUS/Stack upgrade with USB bootloader

[dami]

While reading the UM2237 (STM32CubeProgrammer software description - User manual) data, I came up with a question.

The FUS/Stack upgrade order is explained in Table of Contents 2.7 Flash the co-processor binary using graphical interface.

 

Do I have to connect via ST-Link to do FUS/Stack upgrade?
I tried to do Firmware Upgard using the USB bootloader, but it didn't work.
Also, when connected via ST-Link, all the WB Command buttons are activated, but when connected via USB, the WB Command buttons are deactivated.

question
1. Is it possible to use Firware Upgrade Services using a USB bootloader?
2. Can't use WB Commands button when using USB bootloader? Specifically the Start Wireless Stack button