Using ROCKNIX Guide

Getting Started with ROCKNIX and Pro-tips

To boot into ROCKNIX running on an SD card with Android as the default OS:

1. Start the device in Android and reboot.
2. Before Retroid Pocket logo appears, hold down the Volume-Up button and let go as soon as you see the U-Boot logo (a little submarine icon in the corner)

To always boot into ROCKNIX as the default OS:

1. Hold Volume-Down button while starting device to open loader menu, the abl
2. Use volume buttons to switch modes that include Restart bootloader,Recovery mode,Emergency mode,Switch Boot mode,Power off,START
3. Select Switch Boot mode with vol buttons and press POWER
4. BOOT MODE will switch to Loader
5. Select START with vol buttons and press POWER
6. Use the same process to Switch Boot mode back to Android.

To share games between ROCKNIX and Android:

1. Store your games in /storage/games-internal/roms/ and see ROCKNIX documentation for further details.
2. Let your Android apps gain permissions for this folder.

To access your card after installing ROCKNIX:

Your PC or Mac will no longer read the card through an SD card reader over USB because of its ROCKNIX partition. Try one of these options instead:

1. Use SMB in Windows or macOS to mount SM8250 as a drive
2. Use an SFTP client
3. Use ROCKNIX USB-GADGET mode.

Disable GRUB Menu at Boot

You can disable the GRUB device select screen that appears at boot. This will shave seconds off your boot-time. The recovery option listed has been tested and it doesn't appear to do anything useful when you actually need a recovery.

1. Connect to the rig:
   ssh root@SM8250.local
2. Remount the boot partition read-write:
   mount -o remount,rw /flash
3. Back it up first so it's reversible:
   cp /flash/EFI/BOOT/grub.cfg /flash/EFI/BOOT/grub.cfg.bak
4. Set the menu timeout to 0 — skips the GRUB device-picker wait (edit the EFI config, not /flash/boot):
   sed -i 's/set timeout=2/set timeout=0/' /flash/EFI/BOOT/grub.cfg && sed -i 's/set timeout=-1/set timeout=0/' /flash/EFI/BOOT/grub.cfg
5. Verify both timeouts now read 0 (if either still shows 2 or -1, the remount in step 2 didn't take — redo from step 2):
   grep timeout= /flash/EFI/BOOT/grub.cfg
6. Flush and put it back read-only:
   sync && mount -o remount,ro /flash

Note: ROCKNIX OS updates regenerate the EFI grub.cfg and revert this tweak — re-run these steps after every update.

Internal Storage (Advanced — Optional)

SD-card support was proven first and is the recommended default. For advanced operators who want a faster shader rig, ETK also supports running the shader vaulta and games on the device's internal UFS partition instead of the SD card. This is an optional, opt-in upgrade aimed at intensive shader-harvesting runs.

Retroid Pocket SD8250 devices support ROCKNIX's Install (internal) option which allows the OS to run on a partition inside the internal storage rather than from a partition on your SD card. This dramatically speeds up ROCKNIX boot and OS update times. The ETK also supports the creation of a medium sized internal partition for storing shaders, which improves performance and reduces SD-card treadwear. In addition, the ETK supports the creation of a large internal partition to store games and shaders for improved game launch performance. These partitions take away from your Android storage, so factor that into designing your partitions as your execute the installtointernal.sh command on your rig.

Advancements

• Durability. The shader vault is rewritten every session; moving it off the wear-prone SD card to internal UFS reduces card wear and corruption exposure (the SD is the rig's single point of failure). Shaders write, credit, and survive an R3 recovery correctly on UFS.
• Speed OS boots faster. Games launch quicker. Shader I/O is just better.

Caveats

• Retroid Flip2 firmware supports fastboot over USB in the Qualcomm abl (hold Volume button down during boot) to manage partitions from a host; fastboot in U-Boot is not supported.
• ./install.sh is internal-aware. Once the vault is symlinked into internal UFS, the installer detects it and syncs symlink-safely — no workflow change.
• The internal /storage is also the system partition. Leave ≥1.5 GB headroom; filling it breaks EmulationStation and boot.