1945.1 (= Jan 1945) [U. S. A.] An ignition device for implosion
completed by Luis W. Alvarez.
http://www.ask.ne.jp/~hankaku/english/np7y.html

That was some 4 months before the U-234 episode.

Actually Dr.Alvares completed not one but Three (3) ignitor designs,but none of
them were succesful.Thats the reason why I say "He was unable to produce even
one succesful ignitor design in 18 months"

The last one that delivered to test only hours before was fourth design.

Poor showing of Alvares' first three designs was very well known and documented
fact.
So everbody,including many top Manhattan Projecters were surprised by the
excellent showing of this fourth design in actual test.
After the war ,Alvares always dodged questions about this problem his answer
was always "Well.I cleaned up some wires",.
Well its of course not so simple like Dr.Alvarez made us to believe.
According to Harlow Russ,this fourth design was totally different from the
previous three and included two radical new components and according to Russ
new design these new design was completed "just in time" for trinity test which
explains why the new bomb components arrived to the test site only hours before
actual test.

Alvares' first three designs which your link refers to were so bad that
almost nobody within Manhattan Project believe in success of of Plutonium bomb
test so they concentrated on how to reclaim precious Plutonium from the test
site after failed test.
But to the surprise of the all Manhattan Projecters yield of test was four
times better than their most optimistic estimates.

Why?
Because instead of Dr.Alvarez' junk,superior German technology,or more
precisely the product of universal and eccentric genius von Ardenne, was at the
work in Trinity test site.