Since the old SNES was not built for widescreen displays, the games on the SNES Classic have a border around them to keep the video from looking stretched out (you can change the display to CRT Filter, 4:3, or Pixel Perfect). There are 10 frames to choose from. This tutorial will show you how to add your own custom frames to your SNES Classic Mini.
You will need to have hakchi2 installed before you begin. This tutorial is the same and works for both the SNES Classic Mini and NES Classic Mini.
How-to Add Custom Borders / Backgrounds / Frames to SNES Classic
1. First, we will need to connect to the SNES Classic via FTP (skip to step 5 if you already know how to do this). Run hakchi2 and go to Tools > FTP server on ftp://root...
2. Connect your SNES Classic to your computer and turn it on normally. Wait until the dot on the bottom of the status bar is green before you proceed.
3. Download and install FileZilla here.
4. Run FileZilla, enter the following in the correct fields, and hit Quickconnect:
5. Download the p8173_ownbgs file here and copy the file to /etc/preinit.d
More detailed instruction: In the right window enter "/etc/preinit.d" for Remote site. Now in the left window, locate the p8173_ownbgs file, and drag and drop it into the right window.
6. Download the backgrounds folder in /user/share
More detailed instruction: In the right window, enter "/usr/share" for Remote site, then right-click backgrounds and hit Download.
7. Copy the backgrounds folder downloaded from step 6 to /var/lib/hakchi/rootfs/usr/share
More detailed instruction: In the right window, enter "/var/lib/hakchi/rootfs/usr/share". Now in the left window, locate the backgrounds folder you downloaded from step 6 and drag and drop it into the right window.
8. Now you can add your custom backgrounds folder into the backgrounds folder located in /var/lib/hakchi/rootfs/usr/share
You can download custom backgrounds folder here (make sure you extract the folder from the .zip file and if the files inside the .zip file are not in a folder, just extract them and put them in a folder with the same name as the zip file). To make your own custom background, simply download one of the custom backgrounds and edit the files inside.
9. To change the border, go to Display on the top bar of the main menu.
If you want to set a different frame for each game, read out tutorial here.
If you have any questions, please leave it in the comments below.
Credits: Robin64 of NeoGAF forum