[LEDE-DEV] TP-Link Archer C7 boot loop

[Jochen Demmer]

That actually worked.
Thanks a lot!

On 2016-08-22 23:01, Daniel Golle wrote:
> On Mon, Aug 22, 2016 at 10:30:42PM +0200, Jochen Demmer wrote:
>> Thank you everybody,
>> 
>> I've been trying for 2 hours straight to unbrick via serial, using a
>> prolific pl2303 adapter but without success.
>> 
>> I tried screen, picocom and minicom. I tried Apple's terminal emulator 
>> and
>> iTerm2. Got me a Mac and then Linux. Desperate as I am also connected
>> another C7.
>> I tried like a whole bunch of different settings but no matter what, I 
>> get
>> gibberish characters.
>> 
>> ./picocom /dev/ttyUSB0 -b 115200 -y n -d 8 -p 1
>> 
>> These are the settings I think they should be set to, but it just 
>> won't
>> work.
>> Actually only RX and TX are connected, because when I connect GND the 
>> serial
>> connection freezes and let USB subsystem crash. Connecting VCC doesn't 
>> seem
>> like a good idea, too.
> 
> NEVER connect the VCC of the board to a USB-to-serial adapter!
> 
>> Any hints?
> 
> If connecting the ground causes problems like you described, probably
> the device is really far-off the ground-level compared to the GND of
> the USB port, so when connected you got a non-neglectible current
> flowing and supposedly frying the USB-to-serial dongle. This is often
> caused by crappy power supplies, so if you got a laptop, try running
> it from battery and have the GND connected, that may fix it.
> 
> 
>> 
>> Jochen
>> 
>> On 2016-08-22 11:29, Kevin Darbyshire-Bryant wrote:
>> > On 20/08/16 22:35, Jochen Demmer wrote:
>> > > Hi,
>> > >
>> > > yesterday I bricked an Archer C7 v2 by installing some homebrew
>> > > (buildroot) lede firmware.
>> >
>> > I've only once encountered an issue which I can only assume was a bad
>> > flash.  It's a few months ago so memory is vague.  The serial console
>> > was booting linux but it was reporting something about corrupt
>> > filesystem markers & couldn't mount filesystems.  Even using the tftp
>> > recovery method to re-install factory firmware didn't work...the
>> > factory firmware was having similar partition table issues.  I
>> > genuinely thought I'd bricked it and purchased a replacement that very
>> > morning...with the replacement up & running I then set about seeing
>> > what I could do with the borked unit.  Following the 'serial unbrick'
>> > instructions at https://wiki.openwrt.org/toh/tp-link/tl-wdr7500 I was
>> > able to unbrick it and it's been fine ever since... I'm using it as an
>> > additional access point for downstairs in the house, the new one is
>> > upstairs.
>> >
>> >
>> >        Recovery using serial connection
>> >
>> > Connect to your router via serial, power it up, then type "tpl" until
>> > the boot process is halted and you should be at the console. Set up a
>> > TFTP server with your firmware at 192.168.1.100, then run the
>> > following commands (for v2 only):
>> >
>> > tftp 0x81000000 [name of your firmware file].bin
>> > erase 0x9f020000 +f80000
>> > cp.b 0x81000000 0x9f020000 0xf80000
>> > reset
>> >
>> >
>> > I'm convinced it was the 'erase' command that cleared out some bad
>> > data in the flash.  Like I said, the unit has been absolutely rock
>> > solid ever since.
>> >
>> > Kevin
>> >
>> >
>> >
>> > _______________________________________________
>> > Lede-dev mailing list
>> > Lede-dev at lists.infradead.org
>> > http://lists.infradead.org/mailman/listinfo/lede-dev
>> 
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