BRRRRRRRRRR

Features

• Linux 6.8.2
• bcachefs support w/ zstd compression
• RetroArch 1.18
• Sway
• Upgradable and reset to factory
• Ludicrous mode by default: instant suspend/resume with poweroff fallback
• Ridiculous mode (like quick mode), enable by holding 'A' on startup

How to build

Prerequisites

• A recent Linux distribution (e.g., Ubuntu 20.04 or 22.04, but not 18.04)
• Buildroot and its requirements, as described at https://buildroot.org/
• Additionally, the package libssl-dev has to be installed

There are several ways to set up such prerequisites, e.g.,

• Using an existing Linux distribution, cloning buildroot https://github.com/buildroot/buildroot to buildroot and checking out tag 2024.02.1
• Using a docker, see Dockerfile
• Using a VM, see Vagrantfile

Building the image

1. Clone this repo to brrrrrrrrrr
2. In the buildroot dir, run for i in /path/to/brrrrrrrrrr/buildroot*.patch; do patch -p1 < $i; done
3. Then run make O=rgarc BR2_EXTERNAL=/path/to/brrrrrrrrrr rgarc_defconfig
4. cd rgarc and run make -jN, where N is the number of simultaneous jobs (consider available cpus, cores and hyperthreading)
5. Image to flash will be in output/images/BRRRRRRRRRR-rgarc.img

Note that building the image can take anywhere from minutes to hours, depending mostly on the amount of CPUs/cores available. There are no notable hard disk space requirements.

rg-arc-d users note

rg-arc-d emmc needs to be wiped in order to be able to boot mainline Linux. Note that this is destructive and we cannot take any responsibility. Backup your emmc if you want it back.

1. From power off and sd ejected, hold down power and volume down to get into Android recovery
2. Use adb shell to get a root shell:
3. [Optional] Backup emmc partition: dd if=/dev/mmcblk0 of=<some sd card location> bs=4M
4. Run dd if=/dev/zero of=/dev/block/mmcblk0 bs=512 count=2 or alternatively, dd if=/dev/zero of=/dev/block/mmcblk0 bs=4M to wipe the whole thing.

Usage

Wi-Fi networking

Via RetroArch

1. Ensure Settings > Driver > Wi-Fi is set to "iwd"
2. Setting > Wi-Fi > Connect to Network
3. Select SSID and enter passphrase via on-screen keyboard

Via configuration files

Add iwd ssid config in /boot/iwd/ according to https://wiki.archlinux.org/title/iwd#WPA-PSK and https://man.archlinux.org/man/iwd.network.5

RNDIS USB ethernet

Besides Wi-Fi, the device can also be networked using RNDIS USB ethernet. In this case the device is connected over USB to a host PC which shares its network connection (and may also simultaneously charge the device).

On Windows 11 a suitable driver must be installed manually as follows

1. Connect the DC USB port to a PC
2. Go to the Windows Device Manager
3. Verify device shows up as e.g., Ports (COM & LPT) > USB Serial Device (COM3)
4. Right click > Update Driver
5. Search automatically for drivers > Search for updated drivers on Windows Update > Advanced options > Optional updates > Driver updates
6. Select "Acer Incorporated. - Other hardware - USB Ethernet/RNDIS Gadget", then click Download & Install

SSH and SFTP

You can connect to your device via SSH and SFTP as follows

1. Enable and configure networking
2. Note the device's IP shown in Information > Network Information
3. Connect via SSH or SFTP using login/pass: root / BRRRRRRRRRR

On-device terminal

Connecting an external keyboard to the OTG USB port, you can switch to tty2 from Sway/RetroArch by pressing ctrl+alt+f2, and switch back to Sway/RetroArch by alt-f1. The same login/pass as for SSH and SFTP apply.

Set time zone

To set the time zone for the clock time shown in the on-screen display, there are two options (from SSH)

• Run set_timezone <timezone>, e.g., set_timezone Europe/Berlin
• Run set_timezone (without argument) to automatically geolocate the correct time zone by IP (requires internet set up first)

It may take a minute for change in time zone to take effect in the on-screen display.

On boot

Hold L1 to enter Recovery Menu.

Global

• Power: Suspend
• F + Power: Power off
• hold F show on-screen display
• volup: volume up
• voldown: volume down
• select + volup: brightness up
• select + voldown: brightness down
• F + volup: enable wifi
• F + voldown: disable wifi

RetroArch

Refer to RetroArch settings

Storage

• Filesystems supported: exfat, vfat, ntfs, ext{2,3,4}, bcachefs
• mmcblk1p2 is an ext4 overlay over root /.
• /userdata mounted and tried in this order: mmcblk2, mmcblk2p1, mmcblk1p3, or none (will write directly to overlay in /userdata)

Updating

• Copy rootfs.erofs, initrd.gz, Image, sums to /boot/update/.
• On next reboot, these files will overwrite the existing files on the device

FAQ

Q1: How do I make customizations?

A1: Make changes to this tree and rebuild.

Acknowledgements

• Macromorgan
• JELOS team
• Johnny On Flame
• wuaalb
• Trooper_Max