embedded is a landscape from tiny mcu to imx/h7 style mega beasts; most of the HAL/RTOS/protocols/UI/FS/crypto are in c99; firmware app in c++/rust is possible to take advantage of better abstractions; nobody chooses a language -- however memory safe it may be -- when the whole lifecycle friction is real. besides, rust can't be (meaningfully) faster than c99 in a constrained environment where the resources are typically allocated once and never really released;