Posting multiple copies of the same message is not permitted. I've removed your post from the OCP thread in the Kobo Developer's forum and moved my reply here.
If you look in the .adds/nm directory on your Kobo, do you see a file called koreader? If so, edit it to remove all but the last 2 lines and remove the # from the start of the last line. The original file should look like the first sample below and the modified file should look like the second sample below:
Code:
# Launch KOReader via KFMon
# NOTE: .adds/nm/kfmon will generate this automatically
#menu_item : main : KOReader : kfmon : koreader.png
# Launch KOReader directly via NM (>= KOReader 2020.05)
#menu_item : main : KOReader : cmd_spawn : quiet : exec /mnt/onboard/.adds/koreader/koreader.sh
Code:
# Launch KOReader directly via NM (>= KOReader 2020.05)
menu_item : main : KOReader : cmd_spawn : quiet : exec /mnt/onboard/.adds/koreader/koreader.sh
This will launch KOReader directly from the .sh file instead of detouring through KFMon. If this works, it suggests a firmware update has munged KFMon.
If this doesn't work, you might want to try updating KOReader to the latest nightly release since your Kobo BW has probably updated to firmware 4.42.23296 and this may be causing issues. You can find the KOReader nightly releases at
https://build.koreader.rocks/download/nightly/ and the current as of today Kobo release at
koreader-kobo-v2025.04-121-g4dc4339bc_2025-06-14.zip
Once you have the nightly file downloaded, unpack it and copy the koreader directory into the .adds directory on your Kobo.
Good luck!