HeavenOS is an original, alternative 32-bit operating system for Intel 80386 compatible processors. It is made with NASM (The Netwide Assembler), and is not intended to compare to modern operating systems, but to try to get the best features and discover better ways to do things. It is intended to be a simple and pratical platform for development, running with a small amount of code.
HTCFlasher (formerly known as HERMflasher) is a tool which allows you to flash ROMs on most current HTC devices. It has some extra features that the original HTC RUU doesn't have. For example, it can present a serial prompt to the bootloader (replacing mtty), or it can dump NBH file contents (.nb ROM parts).