Unofficial TRENDnet AC2600 (TEW-827DRU v1.0R) release v19.07.4

Device Support Status

This device is end-user ready. Wired and wireless works, LEDs work, buttons work, and factory image installation works. Testing has shown the system to be reasonably stable. I have a small collection of these devices operating in personal and business environments and they have proven to be reliable.

This document applies only to the 1.0R version of hardware. Other hardware revisions are not compatible nor supported by this release.

OpenWRT/LEDE Project leaders previously rejected all of my patches and I didn't see any situation where it was possible to get them merged so I gave up trying. If someone else wants to take my work and move on with it, you are welcome to do so.

Currently Known Issues

There are no significant issues specific to this device.

Factory installation via the OEM web interface is not supported yet. However, there is a Recovery Loader in u-boot which is fairly easy to use, so we can install our image that way instead. The Recovery Loader itself isn't perfect, but it's safe and bricking this device is rather difficult to achieve.

The "LED on/off" button can't be made to work because we currently can't shut off the ethernet switch port LEDs. This may be fixed in the future if I am able to support it. The button currently does nothing, but it is configured in the DTS so you can write a script to use it if you want to. This button doesn't work under the OEM image either, so nothing lost.

I have seen some stability issues over long periods of time. Every once in awhile (30-90 days) I'll see a sudden reboot of one of the devices I manage. I don't think this issue is specific to the tew827dru hardware because I've seen similar reports on other ipq806x devices.

I am aware there are some minor bugs with the 802.11/WiFi radios. The ath10k CT firmware has a few known issues that can cause poor streaming throughput or disconnects on certain Apple and Android phones/tablets. These issues are not specific to the tew827dru hardware.

Downloads/builds

The latest builds are based off the OpenWRT v19.07.4 releases. My patch set is v17.

Minimal+luci image files are here:

https://jmomo.net/files/lede/TRENDnet_TEW-827DRU_20200910155537_OpenWRT_v19.07.4_luci/bin/

You can download older builds and patches here:

https://jmomo.net/files/lede/

The Minimal+luci builds have a basic bare-bone package set just like you would get from an official OpenWRT release image except with luci-ssl added to provide a web interface. You have roughly 45MB of free space on the overlay to work with.

Recovery and Installation Instructions

Installing OpenWRT/LEDE on this device is very safe, relatively speaking, and it's easy to restore the OEM image if you want to go back.

This device offers three methods for installing images: The uboot http Recovery Loader, the OEM http upgrade tool, and console uboot tftp. However, installation by the OEM http upgrade tool is not yet fully supported.

Most users should use the uboot http Recovery Loader because it's easy and safe to use.

DO NOT use the OEM web/http upgrade page at this time. While the OEM upgrade tool will accept and install the OpenWRT/LEDE image, we don't yet support TRENDnet's "Fail Safe"/safeupgrade dual boot system, which means that the device will revert to the old OEM image after the second reboot.

Finally, you can install images via serial console uboot and tftp.

Be sure to download a copy of the OEM installation images in case you want to go back. See this post for more details.

uboot http Recovery Loader

Connect an ethernet cable from your PC/switch to any one of the ethernet jacks on the router. The Recovery Loader will not start if one of the ethernet ports doesn't go active/up during boot, so make sure you have a live cable plugged in before starting.

Manually configure your computer with an IP on the 192.168.0.0/24 network. The router does not offer DHCP services in this mode.

Press and HOLD down the RESET button on power-up for five seconds. Then release the reset button.

The recovery page will be at at http://192.168.0.1/

The page should say "TRENDnet Recovery Mode" in blue text at the top and there is a "Choose File" button and "Upload" button.

If installing OpenWRT/LEDE, then upload the factory image file.

If you want to go back to the OEM image, use the OEM 1.00b11 firmware file (TEW827DRU_FW100B11.bin), then update to the latest version.

While the file is uploading, the Internet LED will blink. You can watch progress on the serial console too. Beware the progress/percent animation on the https Recovery Loader page is fake/placebo.

That's it. OpenWRT/LEDE should be up and running within 30 seconds of uploading the file. The OEM image takes about two minutes and boots very slowly (due to DFS).

If you are unable to access the Recovery Loader page, or if you upload a factory image and it doesn't install, be sure to read this post. The Recovery Loader is known to be a bit buggy.

OEM http upgrade tool

DO NOT use the OEM http upgrade tool at this time. While our factory image file conforms to the OEM requirements to be accepted and installed, we don't yet support TRENDnet's "Fail Safe"/safeupgrade redundant partition boot loader scheme. The result is that the device will successfully boot into OpenWRT/LEDE after the first reboot, but upon the second reboot it will revert to the old OEM system.

I plan to work on supporting the OEM http upgrade tool and the redundant partition system in the future, but I have not gotten around to it yet.

Console uboot tftp

The serial console on this device is fairly easy to access. A 3.3v/TTL serial port can be found in the corner next to the USB ports. You will need to soldier in header pins. Disassembling the chassis is not difficult.

JP1 = Rx
JP2 = Tx
JP3 = Ground
baud = 115200

uboot gives a 2-second "Hit any key to stop autoboot" prompt, so that's easy to break. No special key combo required.

This device uses a FIT archive file, which includes an installer script, a bootconfig image, and the UBI (kernel+squashfs+ubifs). All we really need to do is tftp the factory image into memory and execute the script embedded within it.

setenv ipaddr 192.168.0.1
setenv serverip 192.168.0.2
setenv netmask 255.255.255.0
tftpboot 0x42000000 openwrt-ipq806x-trendnet_tew827dru-squashfs-factory.bin
setenv imgaddr 0x42000000
source 0x42000000:script
reset

Future Plans

JTAG recovery is something I want to do some day. It may be possible to recover from JTAG by booting from RAM or programming the NAND flash on this device. I've already experimented with this and had some progress but I've not yet figured everything out and I regret that I don't have time to work on it right now.

Expand the NAND partitions, or otherwise fully use the NAND flash space. The default "rootfs" partition is 64MB in size, but there is 108MB of completely-unused space on the NAND flash, outside of smem/mtd partitions. There is also an additional 64MB of space used by the redundant rootfs_1 partition. It may eventually be possible to have a rootfs file-system of 228MB in size. If you want to use that 108MB of free space right now, see this thread on how to set up and use the "freespace" partition.

Custom u-boot. This depends upon being able to safely recover. We would need either TRENDnet's broken "Fail Safe" system to be fixed, or JTAG recovery. Otherwise the risk of permanently breaking the device is too great.

Boot from USB. This is not possible right now because the OEM u-boot wasn't built with the right modules. This would require building a custom u-boot.

Previous Forum Threads and Old Development Info

In May of 2018 the old OpenWRT forum died due to negligent administration. Previously, this is where I had kept a running log of changes and updates for this device.

This new thread replaces and supersedes any information on the old forum, but you can still read the old thread for background information on how I ported the device, previous issues, and additional technical information.

The old forum thread can be read here:
https://forum.archive.openwrt.org/viewtopic.php?id=65956

The original (now potentially invalid) URL to the old forum was:
https://forum.openwrt.org/viewtopic.php?id=65956

Then in 2019 the powers that be decided that it was a good idea to prevent the editing of forum posts after a short period of time, to combat some spam mechanics. Thus I intend to start a new thread for each new release since I can no longer edit my posts.

Previous release threads can be found here:

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Note I am no longer publishing the non-luci Minimal image files.

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Also, OpenWRT has a new announcements mailing list. If you've not done it already, and you want to get an email every time OpenWRT releases a new version, you should sign up!

https://lists.openwrt.org/mailman/listinfo/openwrt-announce

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