[Q] Path Substitution Not Working topic

I picked up a USB flash drive to use for my Kodi thumbnails so I wouldn't keep running out of space on my Fire TV. I mounted the drive using stick mount, then added the code below to my advancedsettings.xml file, but I don't believe it's working. I'm assuming that when I pop the flash drive into my computer, I'd be able to see a bunch of thumbnail files on there, wouldn't I? But my thumb drive is blank. Below is the code I'm using. Am I missing something? Is my path in the TO line not specific enough? (I created an "xbmcthumbnails" folder on my flash drive.)

<pathsubstitution>
<substitute>
<from>/storage/emulated/0/Android/data/org.xbmc.kodi/files/.xbmc/userdata/Thumbnails/</from>
<to>/storage/usb/drive1/xbmcthumbnails/</to>
</substitute>
</pathsubstitution>