How-To flash A-H BLHeli_S firmware

This is a quick how-to flash an A-H BLHeliS firmware, when your ESC support it, but you can´t see the firmware in the BLHeli Suite software.

Example: You have a Racerstar MS ESC, which has a BB2 MCU and should be able to use the A-H type firmware, but you only can choose an A-L firmware.

Open BLHeli Suite, go to “Options” and choose “Expert Mode”.


Then connect your ESC and proceed to flashing BLHeliS firmware. Click on “Ignore inappropriate MCU” and then you will be able to choose the A-H firmware.


Please note that your ESC should in theory support that firmware, so double check before flashing or you can damage it.

Leave a Reply


  1. Montis

    Nice how-to. But please have in mind that there are Racerstar ECS’s with BB1 MCU ( Racerstar MS Lite). They should be flashed with A-L firmware.

    • Sergey

      Hey Montis, thanks for mentioning that. Just checked it and notice that there is Lite version of the Racerstar MS. Best, Sergey

  2. Nick

    Thanks! But do you know the improvements?

    Greets Nick

    • Sergey

      Hey Nick, not sure if there is any real noticeable improvement…