Here’s a quick tip on how to look up a saved wifi password on your Android handset. Let’s say you need to flash a new rom but you don’t have a password written down for a wifi access point you frequently use. Use any file explorer on your Android handset and navigate to the /data/wifi directory and view the bcm_supp.conf file. This is just a basic text file that contains all your wifi access points and passwords that you’ve used previously.
Make a backup of it or simply write down the password you need, enjoy!