Channel shortening is often necessary for mitigation of inter-symbol and inter-carrier interference in multicarrier transceivers. The MERRY algorithm has previously been shown to blindly and adaptively shorten a channel to the length of the guard interval in a multicarrier system. In this paper, MERRY is modified to remove the square root and division needed at each iteration, with the added benefit of allowing the use of constraints other than a unit norm equalizer; an extension is proposed which allows for the use of more data in the MERRY update; the algorithm is generalized to the MIMO case; and blind symbol synchronization and initialization techniques are proposed. Simulations demonstrate the success of the algorithm and the synchronization technique in a MIMO setting.