Welcome to INAV 9.1.0-RC1

Please carefully read all of this document for the best possible experience and safety.

Contact other pilots, share experiences, suggestions and ask for help on:

	INAV Discord Server
	INAV Official on Facebook

This is a Release Candidate. RC builds are for testing purposes. If you find issues, please report them on GitHub Issues.

INAV 9.1 is primarily a maintenance release focused on reliability improvements, safety fixes, and GPS accuracy. It contains no incompatible settings changes — your 9.0.x diff all will load cleanly.

Note

The INAV 9.1 Configurator includes a settings migration tool in the CLI tab that can assist with upgrading from older versions (7.0+).

Manually Upgrading from INAV 9.0.x

Download and install the new INAV 9.1 Configurator
Backup your configuration: CLI → diff all → save to file
Flash INAV 9.1.0 — Full Chip Erase is NOT required when upgrading from 9.0.x
Restore settings from CLI or use the Keep current settings option

Manually Upgrading from INAV 8.x

Download and install the new INAV 9.1 Configurator
Backup configuration: CLI → diff all → save to file
Flash INAV 9.1.0 WITH Full Chip Erase enabled
Load your 8.x diff into the CLI; note any settings shown in RED
Use the INAV CLI Update Tool or manually update incompatible settings from the 9.0.0 release notes
See Upgrading from an older version for full instructions

⚠️ Important Notes for 9.1

GPS Default Settings Changed

Two GPS defaults have changed. These only affect you if you never explicitly set them in your configuration (i.e., they are not in your diff all):

gps_ublox_nav_hz default changed from 10 → 8 Hz. Lower rate allows more satellite constellations to be tracked for better accuracy, especially on M8/M9 modules. If you want to keep 10 Hz, add set gps_ublox_nav_hz = 10 to your diff.
gps_ublox_use_galileo and gps_ublox_use_beidou now default to ON. More constellations generally improves position accuracy.

Position Estimator — Altitude Controller Gains

Warning

If you have increased nav_mc_pos_z_p or nav_mc_vel_z_p above their default values since INAV 7.1, it is advisable to lower those gains or re-tune them to avoid possible throttle oscillations in navigation modes that control altitude (WP, Cruise, RTH, and forward-flight Poshold).

The improved position estimator relies more on accelerometer weighting, so ensure your multicopter or VTOL is free from propeller and motor vibrations. See Multirotor filter setup for tips.

Highlights

GNSS Constellation and Update Rate

INAV now provides an optimized GPS update rate based on your hardware type (M8, M9, M10) and the number of active constellations. More constellations at lower update rates generally gives better position accuracy. Configure in the Configurator GPS Tab. PR #11262

Multicopter Magless Heading

Pilots flying without a compass can now point the front of their multicopter or VTOL toward a known North heading before takeoff, allowing navigation modes to activate without first flying a short distance to acquire a GPS course. PR #11529

Position Estimator Improvements

Several changes improve multicopter position hold accuracy when GPS signal is poor or fluctuating, with small benefits for fixed-wing navigation as well. #11270, #11322, #11387

OSD Improvements

Post-disarm stats now correctly display CRSF RX data, Saving Setting, and Disarmed by advisories on HD displays. #11506
Multifunction mode expanded with battery voltage/capacity warnings, pitot failure alerts, and compass calibration. #11308, #11543
Toilet-bowl compass deviation warning in Poshold (multicopter). #10854
Surface mode and Geozone system messages improved. #11425

Prominent Bug Fixes

Reversed throttle servo safety fix — Fix servos outputting wrong position when disarmed with reversed throttle mix. #11318
RTH Trackback lockup fix — Prevents flight controller locking up in some RTH Trackback scenarios. #11393
4-in-1 ESC random motor spin-up — Fixes motor 1 random spin-up after disarming with BLHeli_32 32.9 and earlier firmware. #11260
Althold manual climb rate — Climb rate now correctly meets the target setpoint. #11359
CRSF telemetry corruption — Fix airspeed, RPM, and temperature telemetry corrupting the data stream. #11189
SD card lockup — Timeout guards for SD card SPI and SDIO drivers when using problematic SD cards. #11321
USB VCP disconnect lockup — Fix USB serial port lockup on device disconnect. #11351
MSP over telemetry — Fix multi-frame request assembly blocking and reduce congestion. #11478, #11481
Blackbox overflow — Prevents overflow in blackbox acceleration and vibration fields. #11447
Virtual pitot GPS failure — Better handling of virtual pitot when GPS hardware fails. #11441
Surface mode landing detection — Inhibits landing detection in Surface mode unless AGL altitude is trusted and below 50 cm. #11425

New Hardware Support

New Sensors

ICM-45686 IMU (#11418, #11455)
MS5525DSO digital airspeed sensor (#11467)
SSD1315 OLED display (#10959)

New Flash Storage

XT25F128F (#11590)
MX35LF2G (#11505)

New Targets

AIKONF4V2, BLADE_F4, BLUEBERRYH743, BLUEBERRYF405, Brahma H7, FlyDragon Pro, FLYWOOF405HD, FLYWOOF405PRO, FRSKYF405, HAKRCH743, NEXUS (Original), PAURCF405V2, SDMODELH7V2, SimplyFly H7, TBS_LUCID_H7_OEM, TBS_LUCID_H7_V3

Full Changelog: 9.0.1...9.1.0-RC1
Wiki Release Notes: https://github.com/iNavFlight/inav/wiki/9.1.0-Release-Notes

iNavFlight/inav 9.1.0-RC1 INAV 9.1.0-RC1 release candidate for testing on GitHub