Assembler recommendation: spasm-ng or fasmg
Day 1 recommends using Brass as an assembler, which while Brass is a fine assembler, should be replaced by fasmg, if only because it supports a multitude of output formats and is actively maintained. If not, both spasm-ng and fasmg should at least be mentioned as alternatives, as spasm-ng has traditionally been a fairly common assembler in the community.