If you want, I can provide a tailored sequence for your OS and board — give OS, board/SoC, and how you try to enter loader mode.
based devices (such as the Orange Pi, Radxa Rock, various TV boxes, Chromebooks, and industrial ARM boards) offer incredible flexibility for tinkering. However, the first major roadblock most users hit when trying to flash firmware is the dreaded "No Devices Found" message in RKDevTool (or AndroidTool). rkdevtool no devices found