Build and upgrade prplOS on Banana Pi R4

In the previous article Getting Started with prplOS on Banana Pi R4, we have seen how to explore prplOS Image on Banana PI R4. prplOS is booted using the pre-built image downloaded from the github repo. In this article, we can build our own custom prplOS Image for Banana PI R4 including custom modifications and local patches added to support the new hardware.

prplOS can be built for any OpenWrt compatible devices with custom build instructions tailored to the Target hardware and has several advantages like

1. Explore the prplOS build system and architecture

2. Bring-up new hardware support within prplOS

3. Adapt and configure prplOS to harness all supported features on new hardware

4. Explore prplOS components, features and packages

5. Develop and Integrate new features in prplOS

Build prplOS Image for Banana Pi R4

bpi-r4-dev-resources

bpi-r4-dev-resources is my github repo which contains Banana Pi R4 related dev resources like

• Custom patches

• Build Configurations

• Image artifacts

For building prplOS for the Banana Pi R4 using the prplos-v4.0.0 release, Download the required patch from the bpi-r4-dev-resources github repo

user@linux:[bpi-r4-dev-resources]$ tree --charset=ascii
.
|-- prplos
|   `-- prplos-v4.0.0
|       `-- patches
|           |-- feed_mediatek
|           |   |-- 0001-filogic-Disable-generating-snand-build-artifacts.patch
|           |   |-- 0002-filogic-Remove-eth2-from-WAN-interface-mapping-for-b.patch
|           |   |..... skipped
|           `-- prplos
|               |-- 0001-mtk_filogic-Add-bananapi_bpi-r4-support-in-prplos.patch
|               |-- 0002-uboot-mediatek-Add-latest-uboot-mediatek-from-openwr.patch
|               |..... skipped
`-- README.md

6 directories, 8 files

Setting Up the prplOS Build Environment

For detailed instructions on setting up the build environment, refer to the Building-prplOS page on the official wiki.

1. Initialize prplOS repository

Clone the prplOS repository using the below command and navigate to the prplos build directory

git clone https://gitlab.com/prpl-foundation/prplos/prplos.git
cd prplos

Checkout to prplOS latest stable release, prplos-v4.0.0

git checkout prplos-v4.0.0

2. Add Banana Pi R4 support in prplos

To add Banana Pi R4 support in prplOS, a custom set of patches needs to be applied to the prplos directory.

These patches enable the following features:

• Include Banana Pi R4’s Target Device model name in mtk_filogic.yml, allowing the BPI-R4 to be built as part of prplOS.

• Integrate the latest uboot-mediatek from OpenWrt to add support for Banana PI R4

• Disable Banana PI R4 snand builds since snand support is currently not available

• Enable arm-trusted-firmware and u-boot-mt7988 related packages specific to the Banana Pi R4

• Update LAN and WAN interface names to lan1 and wan, matching the Banana Pi R4’s interface naming

Apply the relevant patches in prplos directory using the follow command

git am ~/Downloads/bpi-r4-dev-resources/prplos/prplos-v4.0.0/Patches/prplos/*.patch

3. Configure Target profile for prplOS build

gen_config.py is a Python helper script in prplOS that simplifies selecting the target device profile and features required for building prplOS images.

It automatically configures the necessary build options, target architecture, and packages based on the selected profile instead of using make menuconfig to select and configure the Target.

To configure the build for Banana Pi R4, run the following command:

./scripts/gen_config.py mtk_filogic prpl security

Here:

• mtk_filogic specifies the target architecture (MediaTek Filogic).

• prpl enables prpl specific packages and configurations.

• security includes additional security-related packages for the build.

4. Add Banana Pi R4 support in feed_mediatek

The feed_mediatek directory contains the below for building prplOS on MediaTek platforms

1. Target related files

2. Kernel related DTS, Configs, Files and Patches

3. Mediatek specific driver and packages

A custom set of patches needs to be applied to the feed_mediatek directory which includes custom changes for necessary image generation and network configurations to build and boot prplOS Image on Banana Pi R4 device

These patches includes the following custom changes

1. Disable generating snand build artifacts

2. Remove eth2 from WAN interface mapping for bpi-r4

Apply the relevant patches in feed_mediatek directory using the follow command

git am ~/Downloads/bpi-r4-dev-resources/prplos/prplos-v4.0.0/Patches/feed_mediatek/*.patch

5. Build prplOS

Finally, start building prplOS with the following make command

make V=e -j$(nproc)

Build Artifacts

Below is the list of prplOS firmware images generated for Banana Pi R4

• SD Card Image - bin/targets/mediatek/filogic/prplos-mediatek-filogic-bananapi_bpi-r4-sdcard.img.gz

• Sysupgrade Image - bin/targets/mediatek/filogic/prplos-mediatek-filogic-bananapi_bpi-r4-squashfs-sysupgrade.itb

Upgrade prplOS Image on Banana PI R4

Method 1 : Burn prplOS Image to SD Card

Burn prplOS Image to SD Card using the instructions provided in the official Banana PI R4 document. Once the Image is burned, Insert the SD Card into Banana PI R4 and switch Boot Jumper to boot from SD.

Power on the Banana Pi R4 to boot your own prplOS Image from the SD card.

Method 2: Image upgrade through Sysupgrade feature

If prplOS Image is already flashed in the Banana PI R4, We can use sysupgrade feature to upgrade the latest image without updating the SD card manually.

• Copy the Sysupgrade Image into Banana PI R4 using the scp command

root@prplOS:/# cat /proc/version
Linux version 6.6.89 (user@3392f6529df3) (aarch64-openwrt-linux-musl-gcc (OpenWrt GCC 12.3.0 r0+25055-4b63d62a00) 12.3.0, GNU ld (GNU Binutils) 2.40.0) #0 SMP Mon Jun 30 05:52:34 2025

root@prplOS:/# scp user@172.16.0.215:~/Downloads/prplos-mediatek-filogic-bananapi_bpi-r4-squashfs-sysupgrade.itb /tmp/
user@172.16.0.215's password:
prplos-mediatek-filogic-bananapi_bpi-r4-squas 100%   36MB  36.0MB/s   00:01

• Upgrade the latest prplOS Image in Banana PI R4 through sysupgrade command

root@prplOS:/# sysupgrade -v -n /tmp/prplos-mediatek-filogic-bananapi_bpi-r4-squashfs-sysupgrade.itb
Mon Jul  7 12:44:40 GMT 2025 upgrade: Commencing upgrade. Closing all shell sessions.
Watchdog handover: fd=3
- watchdog -
Watchdog does not have CARDRESET support
Mon Jul  7 12:34:08 GMT 2025 upgrade: Sending TERM to remaining processes ...

.... skipped ....

Mon Jul  7 12:44:55 UTC 2025 upgrade: Performing system upgrade...
fitblk: /dev/fit0 released
fitblk: /dev/fitrw released
8+0 records in
8+0 records out
Mon Jul  7 12:45:02 UTC 2025 upgrade: Upgrade completed
Mon Jul  7 12:45:03 UTC 2025 upgrade: Rebooting system...
umount: can't unmount /dev: Resource busy
umount: can't unmount /tmp
[  356.673819] reboot: Restarting system

.... skipped ....

BusyBox v1.36.1 (2025-06-30 05:52:34 UTC) built-in shell (ash)

                   _  ___  ____
  _ __  _ __ _ __ | |/ _ \/ ___|
 | '_ \| '__| '_ \| | | | \___ \
 | |_) | |  | |_) | | |_| |___) |
 | .__/|_|  | .__/|_|\___/|____/
 |_|        |_| based on OpenWrt
 --------------------------------
      prplOS 3.2.0-4b63d62a
 --------------------------------

=== WARNING! =====================================
There is no root password defined on this device!
Use the "passwd" command to set up a new password
in order to prevent unauthorized SSH logins.
--------------------------------------------------
root@prplOS:/#
root@prplOS:/# cat /proc/version
Linux version 6.6.89 (user@754c8cc7d26d) (aarch64-openwrt-linux-musl-gcc (OpenWrt GCC 12.3.0 r0+25055-4b63d62a00) 12.3.0, GNU ld (GNU Binutils) 2.40.0) #0 SMP Mon Jun 30 05:52:34 2025

We could now able to build and upgrade latest prplOS Image through various Image upgrade methods in Banana PI R4. It opens up a way to build and explore prplOS architecture through various customizations of our own.

In the future posts, we will cover how to enable, explore WiFi and other prplOS related features in Banana PI R4.