Why does the Rambam not pasken that one can perform a sale מדין עבד כנעני [against shittas Rashi and the seeming pshat in the Gemara that you can]?? Why is it different than Kiddushin?
It is also against the Yerushalmi [Kiddushin 1-3] that says that you can.
Also מעמד שלשתן seems to work מדין עבד כנעני. Otherwise - how is the לוה משעבד himself?