A heuristic entropic-gravity derivation has previously been given of the
gravitational two-body force of modified Newtonian dynamics (MOND). Here, it is
shown that also another characteristic of MOND can be recovered, namely, the
external field effect (implying a violation of the Strong Equivalence
Principle). In fact, the derivation gives precisely the modified Poisson
equation which Bekenstein and Milgrom proposed as a consistent nonrelativistic
theory of MOND.Comment: 6 pages; v5: published versio