Add support for the RTL9303-based Ubiquiti UniFi USW Aggregation, an
8-port 10G SFP+ aggregation switch.
Hardware
========
- RTL9303 SoC
- 256 MiB DDR
- 16 MiB SPI-NOR flash
- 8x 1G/10G SFP+ cages
- Per-port LEDs: 1x white LED per SFP+ cage
- Buttons: 1x Reset
- Console: TTL 3.3V, 115200 8N1, internal unpopulated 4-hole THT
footprint (the device must be opened to solder a header)
- pinout (with the front panel facing you, left to right):
VCC/unused, RX, TX, GND
- Front touch display (see below)
- Software chain:
- U-Boot (Ubiquiti-flavoured)
- UniFi OS (OpenWrt-based)
MAC address
===========
Single MAC address derived from the eeprom partition. Applied to all
switch ports.
Front touch display
===================
The unit has a touch-capable front display, driven by a dedicated
STM32-based MCU connected to the host via UART. The MCU runs Ubiquiti's
LCM firmware and exposes a high-level JSON protocol (page selection,
button-press events, etc.); arbitrary pixel-level control is not
possible without replacing the MCU firmware. The display is therefore
not supported beyond what the stock LCM firmware offers.
Disclaimer
==========
Stock uses a dual-bank layout (kernel0/kernel1, 7 MiB each). OpenWrt
replaces both banks with a single contiguous firmware partition.
Flashing OpenWrt overwrites both stock kernel slots; U-Boot remains
intact and can be used for recovery.
The stock firmware blob is RSA-signed and cannot be flashed via the
UniFi web UI. Installation has to be done from a root shell on the
running UniFi OS.
Installation
============
1. Enable SSH on the stock UniFi OS and log in as root.
2. Copy the OpenWrt sysupgrade image to /tmp on the switch (e.g. via
scp).
3. Adjust IMG below to point at the copied file, then run the block as
a whole. It writes kernel0, splits into kernel1 if the image is
larger than that slot (otherwise invalidates kernel1 so U-Boot
cannot pick a stale bank), and reboots:
IMG=/tmp/openwrt-realtek-rtl930x-ubnt_usw-aggregation-squashfs-sysupgrade.bin
K0_BLOCKS=$((0x710000 / 0x10000))
dd if="$IMG" of=/dev/mtdblock2 bs=64k count=$K0_BLOCKS conv=fsync
if [ "$(wc -c < "$IMG")" -gt $((0x710000)) ]; then
dd if="$IMG" of=/dev/mtdblock3 bs=64k skip=$K0_BLOCKS conv=fsync
else
dd if=/dev/zero of=/dev/mtdblock3 bs=64k count=1 conv=fsync
fi
sync
reboot
The switch comes up in OpenWrt after reboot.
It does not matter which bank stock booted from when the dd block
runs: both banks are touched in the same pass (kernel0 written, kernel1
either written or invalidated). With kernel1 invalidated, U-Boot's
internal fallback kicks in and permanently switches to kernel0 on the
next boot, so the device stays on OpenWrt as long as kernel0 is
bootable.
Recovery
========
Since the installation procedure invalidates or partially overwrites
the second bank, recovery requires serial console access (see Hardware
above for pinout).
1. Interrupt U-Boot autoboot by spamming a key during early boot to
drop into the U-Boot prompt.
2. Bring up networking:
rtk network on
3. Transfer an OpenWrt initramfs image via TFTP and boot it:
tftpboot 0x82000000 <server>:<initramfs.bin>
bootm 0x82000000
4. From the running initramfs OpenWrt, re-run the installation
procedure above (the dd block, with $IMG pointing at the image on
/tmp).
Return to stock firmware
========================
There is no fully-supported revert path. The stock firmware blob is a
Ubiquiti UBNT archive (header + parts, see firmware-utils' fw.h) that
embeds a u-boot and a kernel0 uImage payload; only the latter is
relevant when writing back to the kernel partitions.
The snippet below extracts the kernel0 uImage from such a blob by
locating the uImage magic and using the size carried in the uImage
header itself, without parsing any UBNT framing. It is provided as a
best-effort starting point; verify the result before flashing,
otherwise you're on your own:
BLOB=US.rtl930x_X.Y.Z.bin
OFF=$(grep -aboF $'\x27\x05\x19\x56' "$BLOB" | head -1 | cut -d: -f1)
SIZE=$(( $(dd if="$BLOB" bs=1 skip=$((OFF + 12)) count=4 2>/dev/null \
| hexdump -e '1/4 "%u"') + 64 ))
dd if="$BLOB" of=kernel0.uImage bs=1 skip="$OFF" count="$SIZE"
Once you have a clean uImage, write it to both kernel banks (since
the bootselect mechanism is not yet decoded, this guarantees U-Boot
picks the stock image regardless of bank):
dd if=kernel0.uImage of=/dev/mtdblock2 bs=64k conv=fsync
dd if=kernel0.uImage of=/dev/mtdblock3 bs=64k conv=fsync
Link: https://github.com/openwrt/openwrt/pull/23506
Signed-off-by: Jonas Jelonek <jelonek.jonas@gmail.com>
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