TP-Link Archer C20 v5 is a router with 5-port FE switch and
non-detachable antennas. It's based on MediaTek MT7628N+MT7610EN.
Specification:
- MediaTek MT7628N/N (580 Mhz)
- 64 MB of RAM
- 8 MB of FLASH
- 2T2R 2.4 GHz and 1T1R 5 GHz
- 5x 10/100 Mbps Ethernet
- 3x external, non-detachable antennas
- UART (J1) header on PCB (115200 8n1)
- 7x LED (GPIO-controlled*), 2x button, power input switch
* WAN LED in this devices is a dual-color, dual-leads type which isn't
(fully) supported by gpio-leds driver. This type of LED requires both
GPIOs state change at the same time to select color or turn it off.
For now, we support/use only the green part of the LED.
Create Factory image
--------------------
As all installation methods require a U-Boot to be integrated into the
Image (and we do not ship one with the image) we are not able to create
an image in the OpenWRT build-process.
Download a TP-Link image from their Website and a OpenWRT sysupgrade
image for the device and build yourself a factory image like following:
TP-Link image: tpl.bin
OpenWRT sysupgrade image: owrt.bin
> dd if=tpl.bin of=boot.bin bs=131584 count=1
> cat owrt.bin >> boot.bin
Installing via Web-UI
---------------------
Upload the boot.bin via TP-Links firmware upgrade tool in the
web-interface.
Installing via Recovery
-----------------------
Activate Web-Recovery by beginning the upgrade Process with a
Firmware-Image from TP-Link. After starting the Firmware Upgrade,
wait ~3 seconds (When update status is switching to 0%), then
disconnect the power supply from the device. Upgrade flag (which
activates Web-Recovery) is written before the OS-image is touched and
removed after write is succesfull, so this procedure should be safe.
Plug the power back in. It will come up in Recovery-Mode on 192.168.0.1.
When active, all LEDs but the WPS LED are off.
Remeber to assign yourself a static IP-address as DHCP is not active in
this mode.
The boot.bin can now be uploaded and flashed using the web-recovery.
Installing via TFTP
-------------------
Prepare an image like following (Filenames from factory image steps
apply here)
> dd if=/dev/zero of=tp_recovery.bin bs=196608 count=1
> dd if=tpl.bin of=tmp.bin bs=131584 count=1
> dd if=tmp.bin of=boot.bin bs=512 skip=1
> cat boot.bin >> tp_recovery.bin
> cat owrt.bin >> tp_recovery.bin
Place tp_recovery.bin in root directory of TFTP server and listen on
192.168.0.66/24.
Connect router LAN ports with your computer and power up the router
while pressing the reset button. The router will download the image via
tftp and after ~1 Minute reboot into OpenWRT.
U-Boot CLI
----------
U-Boot CLI can be activated by holding down '4' on bootup.
Dual U-Boot
-----------
This is TP-Link MediaTek device with a split-uboot feature design like
a TP-Link Archer C50 v4. The first (factory-uboot) provides recovery via
TFTP and HTTP, jumping straight into the second (firmware-uboot) if no
recovery needs to be performed. The firmware-uboot unpacks and executed
the kernel.
Web-Recovery
------------
TP-Link integrated a new Web-Recovery like the one on the Archer C7v4 /
TL-WR1043v5 / Archer C50v4. Stock-firmware sets a flag in the "romfile"
partition before beginning to write and removes it afterwards. If the
router boots with this flag set, bootloader will automatically start
Web-recovery and listens on 192.168.0.1. This way, the vendor-firmware
or an OpenWRT factory image can be written.
By doing the same while performing sysupgrade, we can take advantage of
the Web-recovery in OpenWRT.
It is important to note that Web-Recovery is only based on this flag. It
can't detect e.g. a crashing kernel or other means. Once activated it
won't boot the OS before a recovery action (either via TFTP or HTTP) is
performed. This recovery-mode is indicated by an illuminated WPS-LED on
boot.
Signed-off-by: Maxim Anisimov <maxim.anisimov.ua@gmail.com>
[adjust some node names for LEDs in DTS]
Signed-off-by: Adrian Schmutzler <freifunk@adrianschmutzler.de>
New U-Boot version for MediaTek MT76x8/MT762x based ALFA Network boards
includes support for a 'dual image' feature. Users can enable it using
U-Boot environment variable 'dual_image' ('1' -> enabled).
When 'dual image' feature is enabled, U-Boot will modify DTB and divide
the original 'firmware' flash area into two, equal in size and aligned
to 64 KB partitions: 'firmware' and 'backup'. U-Boot will also adjust
size of 'firmware' area to match installed flash chip size.
U-Boot will load kernel from active partition which is marked with env
variable 'bootactive' ('1' -> first partition, '2' -> second partition)
and rename both partitions accordingly ('firmware' <-> 'backup').
There are 3 additional env variables used to control 'dual image' mode:
- bootlimit - maximum number of unsuccessful boot tries (default: '3')
- bootcount - current number of boot tries
- bootchanged - flag which informs that active partition was changed; if
it is set and 'bootcount' reaches 'bootlimit' value,
U-Boot will start web-based recovery which then updates
both partitions with provided image
Signed-off-by: Piotr Dymacz <pepe2k@gmail.com>
While most of the target's contents are split into subtargets, the
base-files are maintained for the target as a whole.
However, OpenWrt already implements a mechanism that will use (and
even prefer) files in the subtargets' directories. This can be
exploited to make several scripts subtarget-specific and thus save
some space.
In certain cases, keeping files in parent (=target) base-files was
more convenient, and thus no splitting was performed for those.
Note that this will increase overall code lines, but reduce code
per subtarget.
base-files ipk size reduction:
master (mt7621) 60958 B
split (mt7620) 46358 B (- 14.3 kiB)
split (mt7621) 48759 B (- 11.9 kiB)
split (mt76x8) 44948 B (- 15.6 kiB)
split (rt288x) 43508 B (- 17.0 kiB)
split (rt305x) 45616 B (- 15.0 kiB)
split (rt3883) 44176 B (- 16.4 kiB)
Run-tested on:
GL.iNet GL-MT300N-V2 (mt76x8)
D-Link DWR-116 (mt7620)
Signed-off-by: Adrian Schmutzler <freifunk@adrianschmutzler.de>
