@reyalp, thanks for your reply.
The build info is: CHDK 1.5.1, rev 6085, FW version 100a (though I noticed there is a 100b for download).
I have double-checked the parameters you pointed and the only options toggled on for exceptions are "Disable raw @ burst" and "Warn when exception", everything else is off.
I don't know how useful is this information, but I quickly navigated through _HDKMETA and it has a bunch of garbled files and directory names, with files with 1,7GB and 3,9GB (though this sd card has 4GB). I am assuming it is what it is, but I can't tell you it was always there, it is the first time I check this dir.
Also, without knowing how it was installed by the previous owner, if as a bootable card or not, i do the "firmware update" to make sure CHDK loads.
When I am in the menu of alt mode and press the shutter, it briefly shows the message:
":1: CANNOT FOPEN A/CHDK/SCRIPTS/DEFAULT.LUA"
I don't know if it would interfere since it also happened when dng output was working, but maybe you want these details so I am mentioning it.
Let me know what else you need tested, considering that a "format c: and reinstall" could be inevitable.
Thanks
======= UPDATED AFTER A FEW MINUTES ========
When choosing the option to run a selected script file, I just noticed that there are now a bunch of files with garbled names (just like the attached picture) where there used to be proper lua script names.
It looks like CHDK corrupted itself even with the sd card lock tab on, but I have no idea how.
