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Debricking -- Console access via Serial


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This seems to be a reoccurring topic so I'll go ahead and post links to the resources you'll need to check out. The basic idea is that you can access redboot or a bash console from the serial port on the fon.

The important bits to note here are that a RS-232 to TTL level converter is necessary. You can't simply plug a USB or serial cable into the fon -- the voltage difference will make for a pissed off pineapple.

This adapter can come in board or cable form and can be easily hacked out of cell phone usb cables, build with simple electronics on a bread board, or purchased for under $10.

The other important thing note here is that the Fon won't boot if the serial cable is plugged in. Just power on and plug the cable in a second or two later.

Some good reads:

http://www.digininja.org/fon_serial/

http://www.dd-wrt.com/wiki/index.php/LaFon...rial-Cable-Port

http://microblog.routed.net/2007/02/14/how...evel-converter/

http://www.dd-wrt.com/phpBB2/viewtopic.php?p=63256#63256

http://www.google.com/products?q=serial+TT...r&scoring=p

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  • 5 weeks later...

I was able to gain console access by using the serial cable I had built for my NSLU2. I had to use all four pins which includes the VCC pin because the MAX232 adapter requires the 3.3 volts. You can pick up the adapter from Compsys for $20. Just order A232DBH3v (Max232 RS232 I/O 3 volt Assembled with hood kit). All you need to do is solder 4 wires to it and it's ready to use. I used an old cdrom audio cable that I cut one end off for soldering to the connector. The other end will already have the pins to connect to the serial port on Fon. Here's what the cable looks like connected to my NSLU2:

http://www.siliconempire.net/images/nslu2serial.jpg

http://www.siliconempire.net/images/nslu2b.jpg

Ref: http://www.rwhitby.net/projects/nslu2

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  • 1 month later...

I put off debricking my Fon for a while now because the steps to access the Fon looked far to advanced for me.

I am on break from college, so I have plenty of time to learn new things.

Can anyone help me out with debricking?

I have the wires connected to the Fon [except ground].

The debricking guides say I need a bunch of software with like a billion options...[like cygwin]

I got Cygwin, but have no idea how to use it.

Thats all I have.

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When you plug your serial cable into your machine it will get assigned a COM port.

Use PuTTY, choose serial connection and that serial port

Plug RX and TX cables into the Fon

Power on the Fon

Give it a second and plug in Ground

Hit enter in the PuTTY session a couple of times and you should see a Redboot message asking you to hit control C.

If you want to get into Redboot, hit Control C.

If you just want to get to the console, wait and let it boot. You will be straight in with no password.

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  • 4 weeks later...

Ohh forgot to check this thread;

Thanks for your reply!

So, I plugged in the cable, & was able to open a Putty session.

I hit enter many times, but nothing happened.

I dont have Red Boot installed on my computer, if it is required. [the config got confusing]

EDIT: Wait, RedBoot doesnt belong on the computer does it?

Well, as you can see, I am a hardware haxing noob.

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fon console using USB serial:

My laptop doesn't have an old style RS232 connector so the simplest arrangement is to connect the fon's serial pins to an FTDI serial-to-USB converter. Here's a $15 item from SparkFun:

http://www.sparkfun.com/commerce/product_i...products_id=718

Connect RxD, TxD and ground from the fon to this device (swapping TxD and RxD), connect with a USB cable to your computer and you have a virtual serial port.

Most Linux distros will have the required drivers standard, but Windows requires loading of FTDI drivers:

http://www.ftdichip.com/FTDrivers.htm

Works great with my Vista laptop.

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wOOT Installing the driver got me a connection!

Now this is progress!

I dunno what to do after though.

:D

I was following a guide [Link] & got stuck at step 3.

I downloaded the program & 2 other files, then typed "load -r -b %{FREEMEMLO} openwrt-atheros-vmlinux.lzma" into Redboot. I got back "Can't load 'openwrt-athrtos-vmlinux.lzma': some sort of network error".

Any ideas?

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It means you haven't set up your IP addresses properly. If you are on a Fon you need to have your machine on 192.168.1.1, if you are on a Fon+ or Fon2 you need it to be on 192.168.1.254.

Then make sure you have your tftp server running and can grab the files you are requesting from it.

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What do you mean by stuck, step 9 is just brining the Fon back up with the OpenWrt install on it. You now have a working OpenWrt machine.

For me, the next step would be either telneting in and setting the root password or doing it through the serial connection. After that just use OpenWrt.

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This is what I did.

STEP 8, reboot

STEP 9, wait until fs is created

== Executing boot script in 10.000 seconds - enter ^C to abort
RedBoot>

I waited, but only got the Redboot> thing.

The guide says I should get this:

...
br-lan: port 1(eth0) entering learning state
br-lan: topology change detected, propagating
br-lan: port 1(eth0) entering forwarding state
PPP generic driver version 2.4.2
jffs2_scan_eraseblock(): End of filesystem marker found at 0x0
jffs2_build_filesystem(): unlocking the mtd device... done.
jffs2_build_filesystem(): erasing all blocks after the end marker... done.
mini_fo: using base directory: /
mini_fo: using storage directory: /jffs

Any ideas?

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== Executing boot script in 10.000 seconds - enter ^C to abort

If you are getting this message and then after 11 seconds of you not touching anything it is dropping to a redboot shell then you need to do this to tell it to load and execute the OS you just installed.

RedBoot> fconfig
Run script at boot: true
Boot script: 
Enter script, terminate with empty line
>> fis load -l vmlinux.bin.l7
>> exec
>> 
Boot script timeout (1000ms resolution): 2
Use BOOTP for network configuration: false
Gateway IP address: 
Local IP address: 192.168.1.1
Local IP address mask: 255.255.255.0
Default server IP address: 192.168.1.254
Console baud rate: 9600
GDB connection port: 9000
Force console for special debug messages: false
Network debug at boot time: false
Update RedBoot non-volatile configuration - continue (y/n)? y
... Erase from 0xa87e0000-0xa87f0000: .
... Program from 0x80ff0000-0x81000000 at 0xa87e0000: .
RedBoot> reset

This will be a one off thing, after this it should reboot and drop into openwrt.

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  • 4 weeks later...

I created a couple of shares w/o restrictions and enabled CIFS, HTTP/S and FTP/S. On the Standard Files Protocol menu I have turned on FTP access, Port 21, User Authentication. I can get to the shares via CIFS, also via HTTP, but cannot get to the shares via FTP. Both the ReadyNAS and the desktop are on the same LAN. Any Ideas? Thanks

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I created a couple of shares w/o restrictions and enabled CIFS, HTTP/S and FTP/S. On the Standard Files Protocol menu I have turned on FTP access, Port 21, User Authentication. I can get to the shares via CIFS, also via HTTP, but cannot get to the shares via FTP. Both the ReadyNAS and the desktop are on the same LAN. Any Ideas? Thanks

Wrong thread, but you will also need to open up port 20(and 21) for ftp.

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  • 1 month later...

Is the ground problem only on the 2200, I'm on the 2100 and I seem to get into redboot with ground already connected. I want to solder my cable and I was going to put a little switch in it on the ground wire, but if I don't need to I won't.

Also, when I get into redboot, what should I do :|

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The ground thing is hit and miss, sometimes the Fon will boot with it connected, other times it won't. Without it connected though you won't be able to transmit commands so you have to have it connected to send ctrl-c and get into redboot.

Once in redboot do whatever you want - http://sourceware.org/redboot/

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