1. Download UltraISO Floppy, download Ubuntu20.04
2. Check UltraISO, as follows
3. Load the Ubuntu20.04 system iso file
"File" ---> "Open", as follows
4. Click "Start" --> Write hard disk image
The result is as follows:
5. You can choose to format the U disk first, the result is as shown below
6. Select the writing method: usb-hdd, do not use usb-hdd+.
7. Click "Easy Startup" ---> "Write New Drive Boot Area" ---> "Syslinux" (this step is very important, don't miss it)
8. After the boot sector is written, you can click the "Write" button
9. After the writing is complete, click "Return" to complete the creation of the ubuntu20.04 system installation U disk.