Linear B syllabograms, homophones and special characters missing from the Linear A syllabary:
A considerable number of Mycenaean Linear B syllabograms, homophones and special characters missing from the Linear A syllabary. But the same can be said for a fairly large number of Linear A syllabograms, homophones and special characters missing from Linear B. Thus, students of both syllabaries must master, first the overlap, which accounts for most of the characters in both syllabaries, and secondly, the discrepancies, of which there are scores. There is simply no way around it. If you are a student of both Linear A and Linear B you have to learn the syllabograms, homophones and special characters found in one of the syllabaries but missing in the other.
Notably, the O series of syllabograms in Linear B suffers from several lacunae in Linear A. This is simply because Linear A has an aversion the ultimate O, and nothing more. Words which terminate in O in Linear B, which is to say, masculine and neuters, much more commonly end in U in Linear A. And this includes a great many exograms which are common to both syllabaries.
Above all else, the masculine and neuter genitive singular always terminates in O in Linear B, and always in U in Linear A. The feminine genitive singular ultimate in Linear A, just as we find in Linear B, appears to be ija, and there are plenty of examples (for instance, jadireja, kiraja, kupa3rija, musajanemaruja, namarasasaja, nenaarasaja, nemaruja, nenaarasaja, nukisikija, sejarapaja, sidija, sudaja and Sukirteija, to cite just a few) . The problem is that no examples of masculine or neuter genitive singular with the ultimate ijo exist. Only a few words terminate in iju, (aju, araju, kumaju, kureju, pirueju and sareju), but these are almost certainly masculine and/or neuter genitive singular, hence likely validating the notion that the feminine genitive singular is ija.