Sometimes flashing the USB won't work or you want to use an USB that had other Linux versions flashed on. In such cases, you will need to do a full restore of your USB as simple format won't be sufficient. You will certainly need to do that, if after flashing you don't have the access to the USB and can't edit the config.js file.
If you are using Windows, first open a Command Prompt (cmd.exe) as an administrator and enter the following commands step by step.
diskpart (this will run new diskpart window)list diskselect disk x (with x being the disk number of your USB)clean (in case you get an error on this step, unplug the USB and plug it back in and start from beginning)create partition primaryactiveformat fs=fat32 quickexitThis procedure will restore your USB to its original state.
If you are using Linux, you will need to delete the old partitions that remain on the USB first, then create a new partition. First, open the terminal and then enter the commands step by step.
sudo sufdisk -l to see the letter of your USBfdisk /dev/sdx (with x being the letter of your USB)d to delete a partition1 to select the first partitiond to delete another partitionn to make a new partitionp to make this partition primary1 to make this the first partitionw to write the new partition information to the USBumount /dev/sdx1 (with x being the letter of your USB)mkfs.vfat -F 32 /dev/sdx1 (with x being the letter of your USB)This procedure will restore your USB to its original state.