Raspberry Pi Installation Help?

[meda20]

Raspberry Pi 2B 1GB; Power supply rating: 2,5A; SD card: Kingston 8GB (10)
Network (Ethernet): 1Gbit; Connected devices: HDMI monitor FullHD, USB disk 16GB, USB keyboard.

Hello, I have a question about installing XBian on RPi 2B.
(XBian_2022.09.30_rpi4 /3/2 with Kodi 19.4)
I am installing on SD card, I will start the configuration first. After reboot, I perform a clone to a usb flash drive.
On the RPi 2B the hardware cannot be set to boot from USB.
The question is:
How do I modify the system boot files on the SD card so that the other part of the system and kodi will boot on the USB flash drive?
Thanks for the detailed step by step help, if possible.
Thank you very much.