android: how to clear restrictive permissions on internalSD background - symlinking gone wrong from internalsd to externalsd on android 7, that makes the CrypticFolderName inaccessible to the app that needs it.  

https://forum.xda-developers.com/android/apps-games/apps2sd-partition-sd-card-link-apps-to-t3122919/page443

i'm at terminal via ADB i get:  

cd CrypticFolderName  
/system/bin/sh: cd: /sdcard/tencent/micromsg/CrypticFolderName: Permission denied  


as SU:  

chmod -R 777 CrypticFolderName  
chmod -R 777 CrypticFolderName  
chmod: No CrypticFolderName: Permission denied  
:/storage/emulated/0/tencent/MicroMsg #  


but if i do ls -la on the folder above in the tree, the CrypticFolderName is listed with the same permissions as the rest of the folders, that are accessible.  

drwxrwx--x 26 root sdcard_rw 4096 2017-12-12 12:16 CrypticFolderName


what to try next? or - do i need to format the partition that the sdcard is on? which partition is it on? does TWRP wipe do a format?
not really an answer, but i ended up resolving the issue by reformatting the data partition on the phone and restoring the data on to it with the help of TWRP. the wrong permission / dead symlink / whatnot got removed and was not present in the TWRP backup.

this thread pointed me there:
https://forum.xda-developers.com/g5/help/please-xt1675-stock-fastbboot-firmware-t3692083/page2#post74872938