Source: MSX Forum
Yesterday, Clifer started this forum thread, in which he pointed to an article he wrote on updrading a Panasonic MSX2+ computer to 512kB RAM with 16bit * 1M DRAM. The documentation on how to perform this upgrade yourself is available as a web page right here, or can be downloaded as a PDF file from here.
Relevant link: MSX2+ 512kB upgrade howto (web version)
