BarberUA

Flashing from USB is done by the bootloader (the BIOS of the box), which is installed in the factory by VU+. Not related to OpenPLi (or any other image), and nothing we can control.
 
The Solo2 is an old box, make sure you use a small (1Gb / 4Gb) USB 2.0 stick, and make sure no other USB devices are connected to allow the bootloader time to detect it.
 
And what do you mean with "I insert the USB flash drive into the receiver, select the online firmware, and thus the receiver begins to flash"? What is "online firmware", and where do you select it?

 
menu. settings . image firmware.

Try flashing 8.3-release, and if that works, flash 9.0 from the menu?

I downgraded the firmware. but it is impossible to flash from a flash drive. I downloaded the zip file, put it on flash and flashed it. Now even the factory firmware cannot be flashed. Now, to flash the new firmware, I insert the USB flash drive into the receiver, select the online firmware, and thus the receiver begins to flash. why is that? it is not comfortable.