ChibiOS/RT is a compact and fast RTOS designed for embedded applications. It offers threads, mutexes, semaphores, messages, events, timers, flexible I/O with timeout capability. ARM7, Cortex-M3, AVR, MSP430 and x86 are currently supported.
OpenBLT is mostly used as an STM32 bootloader, due to the popularity of STM32 microcontrollers. However, the bootloader’s architecture is such that it can work with any microcontroller and use any type of communication interface to perform firmware updates.