Dual SD Card Migration¶

KNULLI runs fine as a single SD card CFW. However, some KNULLI-supported devices have more than one SD card slot which gives you the opportunity to run KNULLI in a dual-SD-card setup.

This guide is not applicable if you already run a dual SD card setup

This guide was written specifically for migrating from a single SD card setup to a dual SD card setup.

Advantages¶

It is not technically required to run KNULLI in a dual-SD-card setup. However, using two dedicated SD cards for your KNULLI device brings a couple of advantages:

Updating KNULLI is significantly easier if all your games, saves, configurations, etc., are stored on a dedicated SD card. You can always simply shut down your KNULLI device, remove your primary SD (which has only the OS) and simply re-flash it with the newest version without a single worry about your user data. (Technically, for most KNULLI updates it is possible to just do a manual update as explained in the Update section. However, some updates require to re-flash, which will be less of a hassle if you run with a dual-SD setup.
Switching devices is easier. Since some KNULLI-driven device are somewhat different, it might be required to remove your system folder and reboot to re-configure KNULLI from scratch if you migrate to a different device. However, all your games, BIOSes, screenshots, themes, saves, decorations, etc. can still be easily transferred to a new device if you simply plug your old SD 2 into your new device.
Backing up your user data can also be significantly easier if you can simply duplicate the entire SD card, e.g. by drawing an image from your original SD 2 and flashing it onto a new SD card.

How to migrate¶

Before you start to migrate, make sure that you have the following tools at hand:

your KNULLI-driven gaming device
means to charge your KNULLI-driven device
a primary KNULLI SD card
a second SD card ready to be formatted
a computer
a working SSH connection to your KNULLI device

Make sure that KNULLI uses internal storage¶

On your KNULLI device, press the Start button to bring up the main menu.
Go to System Settings and find Storage Device in the Storage section.
Make sure that Storage Device is set to Internal.
Reboot your KNULLI device.

Format the second SD card¶

Shut down your KNULLI device.
Add the new SD card that you want to use for your user data into the secondary SD card slot (TF2/Ext.) of your KNULLI device.
Turn on your KNULLI device.
Press the Start button to bring up the main menu.
Go to System Settings and find Frontend Developer Options.
In Frontend Developer Options, find Format A Disk in the Tools section.
In the Format A Disk menu,
- make sure to pick your secondary SD card as Device To Format. (You should be able to recognize it by its size. Make sure not to format the "internal" device!)
- make sure to pick the file system ext4. (Technically, it is also possible to format to exfat, but we do strongly advise against that, because exfat has only very limited PortMaster compatibility as explained here.)
- select Format Now after making the settings explained above.
Keep an eye on the upper-right corner of the screen where the formatter will inform you about its state.
Reboot your device when the formatter appears to be done: Press Start to bring up the main menu, head to Quit, then pick Restart System.

Back up your user data¶

Press the Start button to bring up the main menu.
Go to System Settings and find Backup User Data in the Storage section.
In the Backup User Data menu, set Target Device to your secondary SD card (usually, you only have one single option here, which corresponds to your secondary SD card).
Select the Start button at the bottom of the screen after setting up your Target Device.
KNULLI will back up your userdata to the second SD card now, which might take a while. Depending on the size of your user data folder, it might be required to plug the charger cable to make sure that the device will not run out of battery while copying your data.
When copying is done, you will see a window with the word Finished and an OK button.
Hit the OK button.

Move your user data within your secondary SD card¶

At this point, all your data has already been copied to the second SD card. However, the backup tool creates a folder batocera on your SD 2 and stores all your userdata inside that folder. Unfortunately, KNULLI expects all this data outside of the batocera folder, so we have to move all the files now within your SD 2.

This section might look a little bit scary to Linux beginners, because we run a lot of text based commands in this section. However, don't be scared, as this guide will lead you through the process.

Some basic Linux commands

In this section, we will use three text-based Linux commands to navigate your data storage and move files around.

cd - means change directory, a command to enter or exit directories (also known as folders)
ls - means list, a command to list the contents of a directory
mv - means move, a command to move files and directories

Establish your SSH connection.
On the SSH prompt, type
```
cd /media
```
and press Enter to navigate into the media folder of your KNULLI file system.
Notice that your prompt has changed to
```
[root@KNULLI /media]# 
```
where /media indicates which folder you are currently inside of!
Inside the /media folder, type
```
ls -lHa
```
and press Enter to list the contents of the /media folder.

You should see that your /media folder contains 3 subfolders: BATOCERA, SHARE, and SHARE_1. The output of the ls -lHa command should look something like this:

drwxrwxrwt  5 root root  100 Oct 29 22:51 .
drwxr-xr-x  1 root root  160 Oct 29 22:51 ..
drwxr-xr-x  5 root root 4096 Jan  1  1970 BATOCERA
drwxr-xr-x  4 root root 4096 Oct 29 22:53 SHARE
drwxr-xr-x 16 root root 4096 Oct 29 22:05 SHARE_1

One of the two SHARE folders corresponds to your SD 1, the other one corresponds to SD 2. Unfortunately, you cannot be sure which is which, so you have to explore both folders to learn which is which:
Type
```
ls -lHa SHARE
```
and press Enter to see the contents of the SHARE folder, then type
```
ls -lHa SHARE_1
```
and press Enter to see the contents of the SHARE_1 folder.

Only one of them will give you a very simple list of only 2 folders (batocera and lost+found) like this:

drwxr-xr-x  4 root root  4096 Oct 29 22:53 .
drwxrwxrwt  5 root root   100 Oct 29 22:51 ..
drwxr-xr-x 16 root root  4096 Oct 29 22:05 batocera
drwx------  2 root root 16384 Oct 29 22:50 lost+found

This is the folder you want, this is your SD 2 folder!

Enter your SD 2 folder by typing cd <name-of-your-sd-2-folder>, so either
- cd SHARE (if your SD 2 folder is SHARE) or
- cd SHARE_1 (if your SD 2 folder is SHARE_1) and press Enter to confirm.
Now, inside /media/SHARE (or /media/SHARE_1) move all the files from inside the batocera folder to the top level of the SD card by typing:
```
mv batocera/{.,}* .
```
(Mind the spaces in this command, be very precise!)
You might see a response like:
```
mv: cannot stat 'batocera/.*': No such file or directory
```
In this case: Do not be alarmed!

Type

ls -lHa

and confirm with Enter to see the contents of your SD 2 folder. The output should look something like

drwxr-xr-x  17 root root 4096 Oct 29 23:34 .
drwxrwxrwt   5 root root  100 Oct 29 23:30 ..
drwxr-xr-x   2 root root 4096 Oct 29 23:34 batocera
drwxr-xr-x  11 root root 4096 Jul 21 04:27 bios
drwxr-xr-x   2 root root 4096 Oct 29 22:05 cheats
drwxr-xr-x   2 root root 4096 Oct 29 22:05 decorations
drwxr-xr-x   2 root root 4096 Apr 12  2024 extractions
drwxr-xr-x   5 root root 4096 Apr 12  2024 kodi
drwxr-xr-x   2 root root 4096 Apr 12  2024 library
drwx------   2 root root 4096 Jul 21 04:29 lost+found
drwxr-xr-x   2 root root 4096 Oct 29 22:38 music
drwxr-xr-x 172 root root 4096 Oct 29 22:05 roms
drwxr-xr-x   2 root root 4096 Apr 12  2024 saves
drwxr-xr-x   2 root root 4096 Apr 12  2024 screenshots
drwxr-xr-x   2 root root 4096 Apr 12  2024 splash
drwxr-xr-x  13 root root 4096 Oct 29 23:30 system
drwxr-xr-x   2 root root 4096 Oct 29 22:05 themes

Congratulations! You have successfully moved all your userdata to the top level of your secondary SD card! Take a moment to be proud of yourself!
To make sure that there are no leftovers, type
```
ls -lHa batocera
```
and press Enter to list the contents of the batocera folder. It should be empty, so it should give you a response like
```
drwxr-xr-x  2 root root 4096 Oct 29 23:34 .
drwxr-xr-x 17 root root 4096 Oct 29 23:34 ..
```
Close the SSH connection - the hard part is already done!

Switch KNULLI to external storage¶

Now, let's get back to your KNULLI device.

Press the Start button to bring up the main menu.
Go to System Settings and find Storage Device in the Storage section.
Switch Storage Device from Internal to Any External or to the specific external device you want to use. As before, it is most likely indicated by its size.
Reboot your KNULLI device to apply the storage change: Press Start to bring up the main menu, head to Quit, then pick Restart System.