Hello all,

THE WORK:

i hope this is not that much off topic, but i wanted to post my first attempt to upgrade the usr5461 wlan router from 8 to 32 mb ram.
I removed the 8 mb "em638325ts-6g" from EtronTech and replaced it with two 16 mb "hyb39s128160ct-7.5" from infineon.
There where two places for holding the two memory chips. (Board: RT-G-BR-02 REV 3.1)

I doubled checked everything twice before i connected the seriell-cable.

THE PROBLEM:

After i connected the seriell-cable and powering on i didn't see nothing.
All the lights came on and shortly after turned off again, instead the power light.
This behavior should be normal.
But it seems that either i screwed my router as a whole or i  just screwed the flash?

THE QUESTIONS:

Now the questions, before i can do further investigations, are:

1. Does the broadcom (bcm5350) chip load the cfe-firmware into the memory (and then starts from there) or does it start directly from the flash?
2. Does somebody know if its normal that theres nothing to see on the seriell-console, if the memory is not installed correctly?
3. Is there a way to check the flash-memory? Where is the JTAG-interface at the USR5461? (There seems to be some connection-parts on the backside at r125, r28, r30 and 31?)
4. Is there something else that comes to mind and i should consider?

If somebody wants to see some pictures of my work, i'll can put them on my homepage or some place else.

I'm thinking of replacing the infineon-chips by other ones, since the default memory-chip from EtronTech where capable of running at 166 MHz and the infineons do only run at maximal 133 MHz.
(This could be a failure too, since i don't know the default memory-clock settings. (e.g. 100 MHz or 166 MHz?))

Thanks in advance!

As far as I know the USR5461 is similar to Belkin F5D7230-4 (1444) and SE505V2. If that's the case, the RAM type you mentioned is OK ( you'll get 16MB, and removing the original 8MB chip has been unnecessary ).

1. the CFE will start from flash, using just registers to initialize the RAM controller

2. if the RAM initialization fails, you won't see anything on the serial port.

3. post a high resolution picture of front and back side of the PCB

4. check for shorted pins and missing components (desolder braid is much more important than a fine tip)

Cheers
/T

Hello,

first of all, sorry for the late reply.
I did some further investigations and put up some pictures here:

http://www.fogman.de/usr5461/img01.jpg
http://www.fogman.de/usr5461/img02.jpg
http://www.fogman.de/usr5461/img03.jpg
http://www.fogman.de/usr5461/img04.jpg

My (un)wiring of the original memory was a little crappy.
I checked all connections twice!
All Address,Data, and so on buses are still connected and (hopefully) functional.
If you remove P902, you have to put a resistor in R33 so that clk is still connected for both memory-chips.

It seems that i broke one/two of my memorys.
So i will do some more testings with a network-analyzer at the university.

Maybe i'm missing something else?

ITS WORKING NOW!

After some effort, i managed to get my WLAN-Router back working!
I will post some more details later!

The only problem now is that its only detecting/using 13 MB of the available 32 MB RAM.
Does somebody here know why or is there some magic i have to apply to the cfe?

Thanks in advance.

(Last edited by fogman on 18 Jan 2007, 18:03)

Hi Timo, if I understand you correctly, I can just make my USR5461 to have a 16MB from an 8MB RAM chip by software. Can you please elaborate this? I sure would like to make my USR5461 to have more RAM without any hardware mods.