Image of Serial Connection to EA2700

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Malachi
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PostPosted: Thu Dec 11, 2014 10:24    Post subject: Reply with quote
LOM wrote:
varidian wrote:
Oh I see, no it did come with usb to serial adapter, and that's good to know about the wires. It tells me which is what on the usb adapter, but the wires don't tell me what's ground, tx, and rx. How can I tell?


Pick a coloured of your choice, write downs it colour on a paper and write GND. Connect one end of the wire to the pin marked GND on your usb-serial adapter, connect the other end of the wire to the GND pin on the router (you have been given the pin numbers in a post further up in this thread).

Pick a different coloured wired, write down its colour on a paper and write TX. Connect one end of the wire to the pin marked TX on your usb-serial adapter, connect the other end of the wire to the RX pin on the router (you have been given the pin numbers in a post further up in this thread).

Pick a different coloured wired, write down its colour on a paper and write RX. Connect one end of the wire to the pin marked RX on your usb-serial adapter, connect the other end of the wire to the TX pin on the router (you have been given the pin numbers in a post further up in this thread).


He didn't buy an adapter. Only wires....

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s-a-g-b
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PostPosted: Wed Jan 05, 2022 6:55    Post subject: Reply with quote
I know this is an old post, but was this recovery successful? I'm trying to restore one of these right now and having trouble. I think the boot loader is corrupt. I didn't have a way to use a serial connection, and used a burner. Is there anyway to restore the boot loader? Manufacturer was no help. I was going to try this method now that I have a new NAND chip on the board with a copy of the old chip. (I'm waiting on a USB to serial adapter to arrive).
s-a-g-b
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PostPosted: Sun Jan 09, 2022 19:17    Post subject: Reply with quote
I connected a USB to TTL adapter to the connection pins and started a terminal program and I get nothing. All the drivers are installed for it. I have RX to TX and TX to RX and Ground to Ground. VCC not connected because the router board is supplying the power. If I type at the console the green light flickers to indicate that data was sent. But all I have is a blank terminal window with a flashing cursor. I previously had the NAND chip off the board to copy it to a new NAND chip. The new NAND chip is currently on the board. I was getting "firmware error" codes with the original chip so incase it had bad segments I replaced the chip hoping that I could successfully flash the updated firmware to the new NAND. I no longer get any status light at all.

I'm thinking that the router's processor is dead.
kernel-panic69
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PostPosted: Sun Jan 09, 2022 20:53    Post subject: Reply with quote
Do you have your serial terminal program configured properly?

https://forum.dd-wrt.com/wiki/index.php/Serial_Recovery

https://forum.dd-wrt.com/phpBB2/viewtopic.php?t=323931

All you should have had to do was either enter management mode (if applicable) and flash stock firmware or trailed mini build *OR* TFTP flash it *OR* do serial recovery. There was likely no need to remove the flash chip. You may have to JTAG recover your router.

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native_tx
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PostPosted: Sat Nov 12, 2022 21:09    Post subject: Reply with quote
I was recently given one of these and was told that it doesn't want to flash the firmware and when using this thread for reference for the serial connection but I'm finding that I can not ctrl-c to access the cfe and so the router continues to boot loop.

I can tftp the oem image but it doesn't it doesn't flash to the proper partition and so it just boot loops.

I figure if I was able to flash from cfe the problem could be solved and so I'd like to ask if the only connecting to the gnd, tx, tx are the only ones? Checking the rx pin seems to not output much power but I don't want to ruin my usb ttl serial adapter.

regards
dale_gribble39
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PostPosted: Sat Nov 12, 2022 21:46    Post subject: Reply with quote
I presume the OP is referring to this post in the (broken) linked thread for the EA2700:

Linksys Cisco EA2700 Serial Dump/CFE ect ect.

So, you're getting output from serial but cannot break boot with CTRL+C by applying power while tapping both keys at the same time? Does hitting the spacebar or any other key work? Does the EA series have a management mode?

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native_tx
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PostPosted: Sun Nov 13, 2022 14:42    Post subject: Reply with quote
I forgot to mention the space bar tapping, I had read the original thread that fractal had posted those many years ago for any other references on breaking into the cfe it is either ctrl-c or check the rx pin and this is when I mentioned that I had checked the power during boot reading seeing less than 3v and my usb ttl serial adapter led doesn't light up and blink when pressing ctrl-c.

I had checked the usb ttl serial adapter on another device and it is working fine, my soldering is skills is good, I'm kinda wondering about the power on the rx pin?

Does this mean connecting the vcc pin to 3v on the usb ttl serial adapter? On another note I had to do something similar to the EA7500v1 to flash openwrt but I haven't read found anything on this model to do similar connection?

I suppose the logical thing to do is check/redo the soldering on the rx pin and measure power output: the power supply adapter is 12v 1.0a, I receive good console reading.

Is fractal still around?

Perhaps if he was/is I am curious if he was ever able to access the cfe? The router boots pretty fast but this isn't a problem as I have already his op and it indicates he was able to do so but was it using ctrl-c, space bar? I've tried them and still not able to be successful.

Currently looking for advise from someone who has gone through the same scenario.

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dale_gribble39
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PostPosted: Sun Nov 13, 2022 20:09    Post subject: Reply with quote
I am doubtful that Fractal is still around or active on the forums these days. I don't have notes handy on voltage tolerances. So, you receive text output from the device's console UART, but nothing seems to pass through from the PC to the console. Have you verified that when you connect the USB-UART adapter TX and RX together that PuTTY echoes your keyboard input as well as testing on another device? Might be possible that solder connection reflow may be necessary. Outside of that, very carefully using a needle in the lead in question and bypassing the in-line resistor (if applicable) or directly connecting to the solder pad underneath your pin header connector may be worth a try.
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"The woods are lovely, dark and deep,
But I have promises to keep,
And miles to go before I sleep,
And miles to go before I sleep." - Robert Frost

"I am one of the noticeable ones - notice me" - Dale Frances McKenzie Bozzio

<fact>code knows no gender</fact>

This is me, knowing I've ruffled your feathers, and not giving a ****
Some people are still hard-headed.

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native_tx
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PostPosted: Mon Nov 14, 2022 2:15    Post subject: Reply with quote
dale_gribble39 wrote:
I am doubtful that Fractal is still around or active on the forums these days. I don't have notes handy on voltage tolerances. So, you receive text output from the device's console UART, but nothing seems to pass through from the PC to the console. Have you verified that when you connect the USB-UART adapter TX and RX together that PuTTY echoes your keyboard input as well as testing on another device? Might be possible that solder connection reflow may be necessary. Outside of that, very carefully using a needle in the lead in question and bypassing the in-line resistor (if applicable) or directly connecting to the solder pad underneath your pin header connector may be worth a try.


Sorry he is not around, but yes there is nothing wrong with usb ttl serial adapter, I did verify it is working another device as well before applying power to the EA2700 the adapter is detecting keyboard input as well with a led, it is when power is applied is when I noticed the led goes out as well the a small led that blinked before power was applied when tapping keyboard testing but not during power is applied it doesn't shine as bright before and so I'm thinking either solder or power is weak on rx pin?

It is a matter of time until I figure something out and so I was hoping that someone that had done work on this model may chime in with an ideal but I guess those times have passed.

Thanks for the reply.

Regards
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