It looks like rusefi has started maintaining a new branch of ChibiOS, with recent developments primarily focused on AT32 / Artery things, hacking at v20 to support rusefi things and backport some specific fixes from upstream. Additionally this branch is re-written against upstream at practically (or just before) the original branches fork.

The new branch is rusefi/stable_20.3.x.rusefi_clean_history, the old branch (one FOME uses) is rusefi/stable_20.3.x.rusefi.

Of note, some important changes are being missed, like:

• ❗ 4556 RTC: do not reset BKP domain if backup clock source is used rusefi/ChibiOS#52
  • RTC and SD logs rusefi/rusefi#4556
  • RTC doesn't survive power cycle #80
  • see FOME-Tech/ChibiOS PRs below break
• ❗ Uart fixes rusefi/ChibiOS#47
  • ChibiOS #1278 STM32 HAL UART ISR flaw
    • ChibiOS fix (v20): ChibiOS/ChibiOS@29bedb3
    • rusefi fix: rusefi/ChibiOS@a173d11
  • STM32: USARTv1: improve baud rate calculation accuracity
    • ChibiOS fix (v21): rusefi/ChibiOS@26f74fc
    • rusefi fix: rusefi/ChibiOS@adeb3c3
• ❗ rusefi/ChibiOS@b3ae9ee
• ❓ Accelerometers mmc rusefi/ChibiOS#42
  • Simplified FatFS bindings. Removed MMCSD experiment files. / MMC Mutual Exclusion support
    • ChibiOS fix (vNext): ChibiOS/ChibiOS@2d9ad10...81475ef
    • rusefi fix: rusefi/ChibiOS@f869830
    • rusefi fix: rusefi/ChibiOS@ad80e27
    • rusefi fix: rusefi/ChibiOS@1e252e5

• stable_20.3.x.FOME: add ChibiOS FOME_STM32_LSE_WAIT_MAX macro warnings ChibiOS#4
• stable_20.3.x.FOME: backup domain reset re: FOME_STM32_LSE_MAX_WAIT ChibiOS#5