Third-Party Notices Skyline Trackers tracker firmware Rev. 2026.09 · covers the firmware image shipped on every tracker, and the strap latch and eyelet This product includes software and a printed design developed by third parties. Their copyright notices and licence terms are reproduced below, as those licences require. Nothing in this file grants rights in the Skyline Trackers name or logo, and nothing here implies that any party named below endorses, sponsors, or is affiliated with Skyline Trackers. Skyline Trackers is not affiliated with SlimeVR. The tracker firmware is open-source software authored by the SlimeVR project and its contributors, used here under the permissive licences reproduced below. -------------------------------------------------------------------- 1. SlimeVR-Tracker-nRF Copyright (c) 2024 sctanf and SlimeVR Contributors Portions Copyright (c) 2025 SlimeVR Contributors Dual-licensed under MIT OR Apache-2.0, at your option. Source: https://github.com/SlimeVR/SlimeVR-Tracker-nRF Skyline Trackers has modified this software. The upstream project remains the authoritative source for the unmodified firmware. 2. VQF-C Copyright (c) 2024 Hugo Chiang — MIT VQF-C is a C port of VQF, the orientation-estimation filter by Daniel Laidig and Thomas Seel (https://github.com/dlaidig/vqf), also MIT-licensed. Credit for the underlying algorithm belongs to its original authors. 3. Bosch Sensortec GmbH Copyright (c) 2020 Bosch Sensortec GmbH. All rights reserved. Copyright (c) 2023 Bosch Sensortec GmbH. All rights reserved. Covers the BMI270 configuration data and the BMM150 / BMM350 magnetometer drivers. Licensed under BSD-3-Clause; full text below. 4. Tlera Corporation Copyright Tlera Corporation — created by Kris Winer Covers the ICM42688 and MMC5983MA drivers. Licensed by its author under the terms: *"Library may be used freely and without limit with attribution."* This notice is that attribution. 5. Peter Bigot Consulting, LLC Copyright (c) 2018-2019 Peter Bigot Consulting, LLC — Apache-2.0 Covers portions of the battery-monitoring code. 6. Zephyr RTOS Copyright (c) the Zephyr Project contributors — Apache-2.0 Source: https://github.com/zephyrproject-rtos/zephyr 7. Nordic Semiconductor ASA — nRF Connect SDK Copyright (c) Nordic Semiconductor ASA Parts are Apache-2.0. The Enhanced ShockBurst (ESB) radio subsystem is licensed under the Nordic 5-Clause Licence, reproduced below. 8. Nordic Semiconductor ASA — nrfxlib (MPSL) Copyright (c) 2018 Nordic Semiconductor ASA The Multiprotocol Service Layer is supplied in binary form under the Nordic 5-Clause Licence. It is embedded here in a Nordic Semiconductor nRF52840 integrated circuit, as clause 4 of that licence requires. 9. ARM Limited (via MPSL) Copyright (c) 2013 ARM Ltd. All rights reserved. The Nordic MPSL library incorporates functions covered by BSD-3-Clause (below). ARM Ltd's name may not be used to endorse or promote this product. 10. CMSIS and CMSIS-DSP Copyright (c) ARM Limited and contributors — Apache-2.0 Source: https://github.com/ARM-software/CMSIS_5 11. SEGGER Microcontroller GmbH — Real Time Transfer (RTT) (c) 1995 - 2024 SEGGER Microcontroller GmbH. All rights reserved. www.segger.com Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following condition is met: - Redistributions of source code must retain the above copyright notice, this condition and the following disclaimer. THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL SEGGER Microcontroller BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 12. Newlib C library The firmware links the Newlib C library (nano variant) supplied with the Zephyr SDK. Newlib is distributed under a collection of permissive licences, chiefly BSD-2-Clause and BSD-3-Clause, held by Red Hat, the Regents of the University of California, and others. The full collection is published as COPYING.NEWLIB: https://sourceware.org/newlib/ 13. Additional calibration routines - magneto1_4.c — magnetometer/accelerometer ellipsoid-fit calibration, credited to sailboatinstruments.blogspot.com ("Improved magnetometer calibration", August 2011) - mymathlib_matrix.c — matrix routines from mymathlib.com 14. Strap latch and eyelet Designed by MoDErahN — https://www.thingiverse.com/thing:6929026 Licensed under Creative Commons Attribution-ShareAlike 4.0 (CC BY-SA 4.0): https://creativecommons.org/licenses/by-sa/4.0/ The printed strap latch and eyelet are made from the designer's files, unmodified. -------------------------------------------------------------------- BSD-3-Clause Applies to sections 3 and 9. Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: 1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. 2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. 3. Neither the name of the copyright holder nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission. THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. MIT License Applies to sections 1 and 2. Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. Apache License 2.0 Applies to sections 1, 5, 6, 7, and 10. Full text: https://www.apache.org/licenses/LICENSE-2.0 The full text is published at the URL above. Nordic 5-Clause Licence Applies to sections 7 and 8. Copyright (c) 2018, Nordic Semiconductor ASA. All rights reserved. Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: 1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. 2. Redistributions in binary form, except as embedded into a Nordic Semiconductor ASA integrated circuit in a product or a software update for such product, must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. 3. Neither the name of Nordic Semiconductor ASA nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission. 4. This software, with or without modification, must only be used with a Nordic Semiconductor ASA integrated circuit. 5. Any software provided in binary form under this license must not be reverse engineered, decompiled, modified and/or disassembled. THIS SOFTWARE IS PROVIDED BY NORDIC SEMICONDUCTOR ASA "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY, NONINFRINGEMENT, AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL NORDIC SEMICONDUCTOR ASA OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.