Using a slightly modified wiper.sh script:
wiper2.sh: Linux SATA SSD TRIM utility, version 2.5, by Mark Lord.
Preparing for online TRIM of free space on /dev/sda2 (ext4 mounted read-write at /).
This operation could silently destroy your data. Are you sure (y/N)? y
Creating temporary file (9995235 KB)..
Beginning TRIM operations..
trimming 19775488 sectors from 513 ranges
FAILED: Input/output error
Removing temporary file..
If I restrict to 512 ranges instead of 513, the trim command succeeds.