FYI - When I purchased the RS232 adapter at Staples last spring the price at the local Staples store was double what is shown on the staples.com web site. The store matched their internet price, so ask for the price match if the marked price is higher than the Staples web price.
I used the 10 ft. version of the StarTech null modem cable (Amazon link below) along with the Staples USB-to-Serial adapter and had no issues with the firmware update.
http://www.amazon.com/StarTech-com-1...ilpage_o05_s00