Boot-loaders are simple but vital programs that run when a system is started.
They generally take stock of low-level conditions, and then initiates a full boot to OS and UI etc.
Most Linux-based STB systems (including Humax STBs) use a boot-loader called U-Boot (or Das U-Boot to hammer in the pun).
The boot-loader on an STB is normally NOT updated, as there is a risk of bricking the device if something goes wrong.
You do not need update your boot-loader if there is nothing wrong with it (the old adage "If it ain't broke, don't fix it").
There are (generally) no UI/UX elements that can be enhanced bya new boot loader.
I don't know what the latest boot-loader is for the 1000S, but I suspect that you would be upgraded automaticlly if you needed an update.