The ornamentation is rough and the body sketchy. The head is
unusually long and thick, and the eyes are big.
The end of the tail has a nice, round
shape but is unusually big.
The sixth rune, th, was probably an initial mistake.
I think Erik might have forgotten the th-rune and
didn't notice until he had already started on the R-rune,
which he then turned into a th-rune.
All S-runes were simplified and only
carved with half a main staff.
The same type of S-runes can be found on
U 793 and U 774.
Erik often had troubles with his S-runes
and might have thought this procedure to be a good solution.
However, his commissioners might not have liked it as much
as he did, and after those three stones,
Erik started using regular S-runes once more.
Below, you can see an article in Swedish on U 1154,
taken from the book Upplands Runskrifter.