-ar in aslakar a mispelling; likewise -u- in staue (from *stabaz)
standardized olden western time ;) :
ósleikr/óslákr gørþi mik (ó = u-mutation of á; leik/lák- variants)
rúnar ek ríst auk ráþna stafi (stafi not stafa - a west norse touch)
........
point of interest: ø in gørþi shown by e not u or o - ø2 not ø1,
being u-mutation of short æ (tailed e), later same as ø1; ø2 is rare
and very hard to find in inscriptions