Now I tried this (I ran the 16MB send trim exe-file, and wait 70 mins). Then I zipped the 16MB-txt-file and attached it here.
TrimTest01.zip (16.4 KB)
Okay, that file shows the first 1MB and last 1MB trimmed but the data in between (1MB-15MB) returning the old test data. Might be the way the firmware works or a problem with it. If you still have the file on disk you could check if GC has changed any of the remaining blocks.