Green Heron Engineering RT-21
firmware v3.08.9
Green Heron Engineering · Released Sep 9, 2026 · First seen Sep 9, 2026
Source:
greenheronengineering.com
v3.08.9 is not the latest firmware for the Green Heron Engineering RT-21: the current version is v4.13.2 (September 9, 2026). Go to v4.13.2
What's in this update
RT-21 Firmware latest v3 Release along with complete RT-21 revision history and load instructions. 3.08.9 for s/n 2000 to 3999 units (v3 ONLY) .zip includes firmware for K7NV (Prop Pitch) and K0XG units as well.
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