UART recovery flash of TPlink Wr104nd v1.8

Hardware Questions and Recommendations
1

Hello,

I do apologize if this is the wrong category for this post. I'm a long time lurker, ddwrt user (I know, I know), first time poster and soon to be openwrt user.

I bought a TPlink Wr104ndv1.8 from Goodwill late last year because it looked alright for $3.99 with the original power cable and all the antennas attached. I failed a flash with ddwrt (strange power failure at the exact wrong time, iirc) and the device only lights up the power light with no recognition from Linux mint, Mac OSX Catalina or Windows 10 when LAN connected (no IP, no communication, no lights besides the lonely steady power light). It was perfectly operational before the attempted flash, although the UI and features were desperately lacking.

I have attempted many, many recovery techniques over Ethernet to no avail. I found them on here and elsewhere. I do not believe it can be recovered in this fashion.

I'm willing to try my hand at something new: firmware recovery with UART/TTL. I'm familiar with electronics (built and troubleshooted many custom PCs over the years) and some light soldering work being, albeit guided most of the time. I will be honest that I'm very unlearned when it comes to exact specifics and uses of resistors, transistors, ICs, etc. But, like I said, I'm learning and I'm very eager to get this router operating efficiently with Openwrt.

Will this usb converter be a good tool for UART/TTL connection to the wireless router in question(TPlink WR104ND v1.8)? If it's great for other projects, such as a raspberry pi, that's fantastic too.

DSD TECH SH-U09C5 USB to TTL UART Converter Cable with FTDI Chip Support 5V 3.3V 2.5V 1.8V TTL https://a.co/d/7ADD8Qx

The reviews on Amazon state it's a genuine FTDI chip and works via plug and play, or with official driver download from FTDI, using Windows 10 and popular Linux distributions. Outside of Amazon, the reviews that I have read contain similar statements. I have been invested in my research of course, noticing the cp2102 USB TTL adapters seem to be most popular and much more inexpensive by far for this type of project, and other projects as well.

I am researching this product as well:

DSD TECH SH-U09A1 USB to TTL Adapter Support 1.8V 2.5V 3.3V 5V Logic Level https://a.co/d/bF5L8Ts

The seller's description and the reviews state it is a cp2102 adapter that seems like a potential candidate to pick up, given that it also covers the same range of voltages for it's purpose of use. I have no brand loyalty to DSD Tech, just what I found on Amazon after researching what tools are required to recover the bad flash. Obviously I'd love something solid, reliable and multipurpose as well.

The other cp2102 adapters I was examining online seem very cheap and highly disposable, low quality products. On Amazon, there are many cp2102 adapters that are about $6 or $8. That seems a little unreasonable given the same exact products are ≤$2 on AliExpress and elsewhere. Most that I looked into seem to only cover 3.3v and 5v, whereas many newer wireless routers can use 1.8v, from what I've been reading at least. I do possess a nice multimeter so I am able to measure the power output of any adapter I purchase so I do not physically damage the wireless router.

If the first item I linked is perfect for this project, and potentially a wide range of others, I'll buy it today. If there is something better out there for me with all the information I've shared, I'll look into it heavily.

Also, if there are is a more 'for dummies' guide than what is on the main page for recovering the TPlink Wr104nd, I will be much obliged to indulge in the knowledge. If not, I will figure it out in time. Again, I am a little unfamiliar with this kind of project, but I'm motivated to recover this router.

Thanks for any help at all, it's greatly appreciated.

2

Be aware that this device is no longer supported, due to its insufficient amount of RAM (https://openwrt.org/supported_devices/432_warning). Given the systems specs (very fragile draft-n/ 2.4-GHz-only wlan, 8/32, relatively slow SOC) it does not make sense to spend money on recovering it, as you can get better alternatives (e.g. tl-wdr3600/ tl-wdr4300 or archer c7 >= v2) for ~5-10 bucks on the used markets or the first mt7621a+mt7915DBDC (wifi6) devices (new/ delivered) starting around 15-20 bucks.

Depending on the chipset, 5-10 bucks are common for serial adapters with quick/ local shipping, but yes, if you can wait 2-5 weeks, you can get usable ones for ~1.5 bucks with slow shipping. If you are a Windows user, you want to avoid fake chips (especially FTDI is prone to being counterfeit), which are commonly found on the market; their linux drivers tend to be more forgiving.

If you are very lucky, the bootloader on your device already supports push-button tftp recovery (see the device page in the wiki), but this was only retrofitted in later OEM firmware upgrade (in 2013?), so you may not have it - if you don't and don't already own all the components necessary, I would not spend any money on recovering it. It simply doesn't make any sense economically.

From a practical point of view, the case isn't that easy to open, but there's worse. TP-Link likes to cut the serial traces (not sure if they did for this h/w revision), you aside from soldering the pin header, you probably have to bridge two missing (tiny) SMD 0-Ohm resistors are well. Once you have serial console access (3.3V, never connect Vcc, only rx/ tx and GND), recovering should be straight forward - if bootloader and wifi calibration data (ART) are undamaged.

Again, you can do it - but I would not spend any money (at all) on resurrecting this device.

1 Like
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I understand it's older and pretty much useless compared to more modern wireless routers on the market today. I suppose I'm using this project as an excuse to further my practical knowledge on soldering and communicating with other devices in ways that I previously thought impossible.

Very informative response and straight to the point. Thanks for sharing some technical advice with me so I can move forward with the recovery more effectively, should I choose to do so. Regardless of it's age and incredible lack of feature set compared to more recent devices, I am still mulling over recovering it and gifting it, with included set up, to my neighbor who is struggling with his own wireless connection problems.

He's rocking at least one mint condition WRT54g at the moment, which seems insane to me if he's paying for anything over 20mbps, and he's vastly under informed concerning technology in general being somewhat of a country fellow. An upgrade seems out of the question for his family, none of my business of course, so it might be a great gift to assist him to the best of my capabilities after all the kindness he's shown me.

The Archer c7 has treated me well until my recent move to a new, larger home where it's struggling to maintain a consistent, reliable wireless connection to my new security system and other existing devices (10-15 I believe), even with ddwrt and highly tweaked configuration. I have only heard bad things about wireless repeaters and perhaps I need an upgrade to my entire network.

What wireless router, with the newer chip sets you mentioned, would you recommend I buy for 15 to 50 dollars (I'm on a somewhat tight budget after a recent PC upgrade) so I can upgrade from the Archer c7 v5? I enjoy the atheros models I've tweaked in the past, including the Archer of course. Are there any brands you're particular of that are known for excellent quality control and high compatibility with Openwrt?

Thank you for the information. I really appreciate it.

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If you are located in the US, walmart might still offer the Belkin rt3200 for around 40 USD, which would be a fairly high-end device for a bargain. In the 15-20 buck range you'd find mt7621a+mt7915 based devices, such as the D-Link DAP-X1860 (only one ethernet port, so avoid if you want a router and not 'just' an AP), D-Link COVR-X1860 or ZyXEL WSM20 (there are large threads for either of them in this forum).

But also check what your local used markets can offer, there probably are quite interesting devices to be found for little money. E.g. the RAC2V1K was selling around 20 USD in used conditions or the Google OnHub (ASUS SRT-AC1900, TP-Link OnHub TGR1900) should be rather cheap, as they've gotten EOL by google and should be sold for scrap. If you need something very cheap/ quickly (the worst in this list, but still strictly better than the TL-WR1043NDv1), TP-Link TL-WDR3600/ TL-WDR4300 might be around for 5-10 bucks on the used markets. The https://openwrt.org/toh/dynalink/dl-wrx36 might be a tad above your price range, but maybe you can find a bargain.

1 Like
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Wow, thanks so much again.

I did manage to get the WR104RND taken apart properly with a guide, it was a little trouble with a couple inner clips. I fired up Terminal in windows and referenced the pics for v1.8 UART. The legit FTDI chip I purchased, AFAIK after googling how one can tell, was set to 3.3v, I clipped the ground and just touched the Rx to the correct spot where a header should have been for Tx on the board, you were correct slh that the headers were not there. The serial settings were all correct, but I didn't get anything but garbage from probing (didn't want to solder headers until I was certain I could receive something at least). I tried putty as well and received the same result. I did not think it necessary to boot up linux after those two failed attempts.

There wasn't any code and it was all very random junk characters. Figured I would come back here and see what that means. I was reading that for some 1.x revisions the ability to SEND commands needs a small jumper soldered to a nearby resistor, but, again, not wanting to do all that if I can't even receive.

I am guessing like you said before that it is completely bricked, trash, without expending much effort to restore bootloader and the Atheros data, if even possible. I am going to call it a lost cause unless I did something wrong, such as: needing to actually solder headers on there, something I missed in the documentation I've poured over (somewhat time limited for a couple weeks), going from the bottom of the board like I saw on Youtube, or something else I may have messed up, this being my first attempt at UART flashing. There are no flashing lights on it, a bad sign I've been reading, just the power light that comes on immediately after plugging in and it stays solid until power is removed. I believe it is completely dead after the failed flash long ago. From what I was reading the bootloader and ART partition (?) were potentially overwritten or destroyed by bad flash and it is beyond anyone's capabilities to get it back..

I have already been looking into the wifi 6 devices you brought up that run on the mediatek chip, having browsed mediateks site. I found the TP-LINK Archer AX20 on ebay for $20 (!). Very easy on the budget and would be very fancy, to me at least.
I could use it as a main router/switch, while the Archer c7 v5 I have on 23.05.2 acts as a repeater where my signal is lacking. Need to do more research, of course, to make sure I am getting the right device for my needs. The Belkin rt3200 is absolutely something I'm interested in purchasing, but I do love my research to be sure it's money well spent with little or no compromise, ALL competition considered.

I greatly appreciate all your help slh. If you believe I can resurrect the WR104RND v1.8 (RIP) somehow still, without needing anymore more specialized hardware, your assistance is more than welcome. It's been a fun little project even without the positive results I wanted.

I am loving this community so far and how in-depth all the documentation is on any device I have looked into that is supported. Very fantastic. Again thanks for all the help. I think I'll keep the FTDI chip just because I am 99% sure it's authentic and could be useful again soon in future devices I mod (given I already FUBAR'd the WR104RND, though it was out of my control). Luckily it was only $3.99 at GoodWill a few years ago and I have a nice little 1.5A wall wart from it at least.

Again, can't thank you enough slh for guiding me down the right path. Soon I will figure out a plan for my Wifi issues concerning the lacking signal at a distance from the WAN. I would like to purchase a wifi 6 router with at least 3 LAN ports so I have multiple options now and in the future concerning use scenarios.

Any thoughts or suggestions on anything at all that I have said will not fall on deaf ears. I am loving the OpenWRT flashing scene.