Straight to the matter, I've been leaving my firmware research work in a state of hibernation for almost a year now due to a (some?) product development work I'm still working on as of now (which I cannot elaborate further). It's not that I feel firmware is not interesting anymore. On the contrary, I feel it's far more interesting now than it used to be due to the raise of connected embedded systems (now re-badged as Internet of Things a.k.a "rather intelligent" data collection systems). The main problem for me is finding time to work on this research again as it's unfortunately not my day job.
As for my work on the continuation of my BIOS Disassembly book project. I will try to find time for that, but I don't want to over-promise on it. Hopefully this clears things up.