Mostly development for Android on Java with use the NDK (C/C++ binary files and libraries).
Develop device software based on embedded Linux with rebuild kernel for specific hardware and custom rootfs. Develop UI of device on QT. Develop software for microcontrollers based on FreeRTOS or bare metal.
Develop hardware based on STM32, AVR and Allwinner board.
ZFlasher STM32 is a program for flashing STM32, STM8, GD32 and AT32 microcontrollers. Supported family: STM32F0, STM32F1, STM32F2, STM32F3, STM32F4, STM32F7, STM32G0, STM32G4, GD32F1, GD32F2, GD32F3, GD32F4, GD32H7, AT32F4, STM8S, STM8L and others.