OpenWrt Forum Archive

Topic: AC1750: Bricked device with no activity on TX line

The content of this topic has been archived on 6 May 2018. There are no obvious gaps in this topic, but there may still be some posts missing at the end.

Hi there,

I got two Archer C7 2.0, both did not boot. I was able to recover #1 with a serial connection and a TFTP setup.

Unfortunately, #2 does not give any activity on the TX line. After pressing the power button, the power LED and all five ethernet LEDs light up, power stays on and the other ones go off again. In fact, they glow very very dimly.
Imagine probing an LED with a multimeter on diode test, with a voltage just above U_threshold. That dim!

I wonder what is wrong with this unit, and of course how to recover it. Would it be possible to dump the flash contents with, for example, the Aardvark SPI programmer, and then write it to the dead unit?

How would you recover such a unit? Is it even recoverable?

Thanks.

fast test, exchange your flash chip with #1 and see how

(Last edited by freewifimarketing.net on 4 Apr 2017, 05:43)

I got it running again. At first I tried recovering it using my Aardvark SPI programmer, but it never detected the flash.
I also tried booting my functional archer, piggy-backed the dead flash to the intact one and severed both vcc and !cs.
Did not work either.

Then I got my segger j-link and tried that. Unfortunately the CPU is not supported by OpenOCD out of the box, so I followed the ath79 patch and had to merge the patch with the git repo files manually. It compiled and connected.

It took the whole night re-flashing the bootloader over jtag, with 4 byte/s. After that it worked like a charm again.

PhreakShow wrote:

It took the whole night re-flashing the bootloader over jtag, with 4 byte/s. After that it worked like a charm again.

I'm trying to unbrick my AC1750, I need the JTAG pinout, could you please post it?

(Last edited by lagoon99 on 3 Jun 2017, 23:09)

The discussion might have continued from here.