Betaflight 4.0.0 Release Candidate 1

Important

This is a release candidate. It is intended for testing, and some things still need fixing and fine tuning. Please use it with caution and report back any issues at https://github.com/betaflight/betaflight/issues. Thank you.

Important information when upgrading

• A number of changes and improvements in this release require changes to the Betaflight configurator. These changes have been added to Betaflight configurator 10.5.0 (to be released in the coming days, installation instructions here). Please update your Betaflight configurator to version 10.5.0 (or newer) as soon as it is available, or use the CLI for now;
• if you are using the Blackbox Log Viewer, there will be an updated version 3.3.0 to go with Betaflight 4.0 (installation instructions here). Please update as soon as it becomes available;
• there are a number of flight performance related improvements in Betaflight 4.0. Therefore, pasting back-ups of the tuning settings for older versions of Betaflight into Betaflight 4.0 will most likely result in poor flight performance! The default settings in Betaflight 4.0 should be reasonably well flyable for most hardware configurations, but users wanting to tune the performance of their craft should read the 4.0 Tuning Notes to learn everything they need to know about tuning Betaflight 4.0 (#6432, #6943, #7078, #7264, #7271, #7304, #7373, #7538);
• there was a fix to how the min_check 'zero throttle' dead zone is applied. Before the fix, the dead zone was essentially doubled. In order to retain the same range for the 'zero throttle' dead zone, you need to double the amount of dead zone configured in min_check (offset from 1000). For users who have set a very small dead zone, this might lead to the dead zone never being reached with the fixed version, not allowing them to arm with a 'THROTTLE' reason even if throttle is at minimum - if you are getting this, increase your min_check (#7463);
• there is a new 'Stick Overlay' OSD element that shows an overlay of the current stick positions. In order to use it, the font loaded onto the OSD needs to be updated to the latest version (available in configurator 10.5.0 or newer) (#7476);
• the functionality of the 'crash flip arrow' OSD element was extended to activate as well when the craft is not in crash flip mode, but small_angle is set, and the craft is unarmed and tilted more than small_angle. This is to show pilots that they won't be able to arm from the current orientation, and allow them to activate crash flip mode and then right their craft (#7250);
• As part of a consolidation of the CLI commands used to manage resources, the resource list subcommand was renamed into resource show. This aligns it with the new dam show and timer show commands (#7712);
• the following parameters were renamed to more closely match their function: p_level => angle_level_strength, i_level => horizon_level_strength, d_level => horizon_transition (#6673);
• unfortunately, bugfixes in the flight controller core functionality have led to an increase of the firmware size, causing it to overflow the available space on almost all F3 based flight controllers. As a result, features have had to be removed from all but a few of the currently supported F3 based flight controllers. Some of the affected targets are: AIORACERF3, BETAFLIGHTF3, CHEBUZZF3, CRAZYBEEF3FR, FURYF3, FURYF3OSD, IMPULSERCF3, LUX_RACE, LUXV2_RACE, MIDELICF3, OMNIBUS, RACEBASE, RMDO, SIRINFPV, SPRACINGF3, SPRACINGF3MINI, SPRACINGF3NEO, STM32F3DISCOVERY (#6900, #6955, #7037, #7038, #7045, #7306, #7381, #7392, #7402, #7421, #7501, #7508, #7518);
• in addition to the above point, the following features had to be removed from all F3 based flight controllers in order to make the firmware fit into flash: Smart Feedforward, support for flashing / configuration of SimonK based ESCs (#7272, #7274, #7391);
• support for status display through LED strips was removed from F3 based flight controllers, in order to be able to reclaim some flash space. In its place, LED Strip Profiles (except for the 'Status' profile which is not supported on F3) can be used to set LED strips to fixed colours. LED strip profiles are also available on F4 / F7, to enable simple configuration of the LED strip in OSD (#7485);
• since the above three measures proved to be insufficient to keep flash space from overflowing on F3 based flight controllers, a system of classifying F3 based flight controllers into a number of 'feature cut' levels, and removing features according from them according to their level were introduced. This was used to reduce the number of features built into most F3 based flight controllers even more (#7429).

Major features:

• real time ESC RPM feedback, and notch filtering based on motor RPM (#7264, #7271);
• d term management with D_min (#7373, #7538);
• throttle based dynamic gyro and dterm filterig (#6943);
• launch control (#6992);
• switchable OSD profiles (#6714);
• SPI attached Spektrum RX (#7210);
• unified targets (#5824, #6837, #7620).

Minor features:

• cascaded dynamic notches (#7078);
• thrust linearisation (#7304);
• integrated yaw control (#6432);
• switchable LED_STRIP profiles (#7303);
• stick overlays in OSD (#7167);
• profile switching based on battery cell count (#7516);
• support for the Futaba SFHSS protocol on CC2500 (FrSky SPI) hardware (#6865);
• EU LBT mode for the FrSky SPI RX (#7339);
• support for STM32F765xx based flight controllers (#6669).
• configuration over HoTT telemetry (#6224).