This is the primary method to restore a bricked HK.T.RT2861V09 board: Use a FAT32-formatted USB 2.0 drive.

The V09 release, confirmed by patch notes from several OEMs (including a leaked document from a Taiwanese networking firm), addresses the following:

: Use a high-quality USB 2.0 drive (8GB or 16GB) formatted to Step-by-Step Installation Guide