Posted: Sat Dec 15, 2007 15:54 Post subject: WRT54G V8 Ram Upgrade from 8 to 32 mb w/pictures!
Hello,
I have recently upgraded my WRT 54g v8's ram from the abysmal 8mb to a 32 mb chip.
It used to be recognized as a 16 mb chip, but it now works and is recognized as a 32 mb chip.
Why i did this mod:
as we all know, lately, linksys has been releasing "cripled" routers, routers with far less flash and ram than before. I have been reading of people upgrading their ram on their WRT. when i first installed DD wrt, it was pretty unstable (that was DD WRT v24 micro RC4). it would crash with about 650 concurrent IPs connected - the cpu would simply go insane. Checking the status page, the Ram used and available were pretty insane, 97% used almost all the time and only a few kilobytes free (3%). thus, i figured this was caused by a memory problem - this was reinforced by RC5, where the memory handling was recompiled (from what i could understand) which increased reliability on my router ever so slightly.
The two chips that i used are described later in this post, in the section "start of "old" topic"
For the desoldering, i used this method:
youtube video on how to desolder surface mounted chips
instead of the pen, i used a very thin needle to lift the pins off - MAKE SURE YOU DO NOT APPLY TOO MUCH PRESSURE. if you do, you might rip off the contacts from the pcb and then you end up with a non working router. (unless you are really lucky and rip off an unused pin)
To put on the chip, i followed this "guide":
as seen in the video, flux is VERY important. i personally used a 5 to 60 watt variable soldering iron with off feature - purchased at radioshack - on the 30 W setting. a Very thin tip is important. Make sure there are no bridges between the pins.
Once the physical chip has been upgraded, the router can be booted. it should boot and if it doesnt (eg. the LAN lights are all on and stay on) then reflow the solder on the ram / make sure they are all making contact. It should detect 16 MB of ram if it worked.
How to enable the last 16 MB for a total of 32 mb:
Log into the router (defaults are 192.168.1.1 user: root/ pw: admin) Go to the administration tab, and then the Commands Sub tab.
then, in the comand window, enter:
Quote:
nvram set sdram_init=0x000a
nvram set sdram_ncdl=0x000
nvram commit
then hit run commands. once you get the prompt that it has been executed, unplug and replug the router. if it worked, the router should now see 32 mb of ram total. if it didnt, the chip installed might not be a 32 mb chip, or it might be defective, or the pin layout might be different (this pinout examination is stressed in the guide i followed).
the rest of this topic contains what was done to obtain these results (and the problems i faced in attempting to get them)
Here are some pictures of my router/steps that i took (click on thumbnails for bigger one)
Before the mod (notice cpu load and active ip connections):
Original Board and ram module:
32 mb Ram Module installed
End result: 32 mb Ram at my disposal!!
Awesome! it doesn't crash at over 650 connections!
Still going!
(start of "old" topic)
however, it is currently being recognized as a 16 mb chip. i assume this is normal, as i have not played with the nvram variables yet.
however, this is where i need help as i am not good in programming at all.
from what i have gathered, if pin A12 is not routed, one will be stuck at 16 MB ram maximum on version 6 of this router. however, my router seems to have pin A12 routed, so this should not be a problem.
the Chip i replaced the original 8 mb samsung chip with is one from Mosel, which was retrieved from a 128 mb pc133 4 chip memory stick. i found that these were pin to pin compatible with the samsung chip, appart from the fact that pin 36 is NC on the samsung chip while it is A12 on the mosel chip.
The mosel chip is v54c3256164vd17, which is a 54 pin TSOP 4 banks x 4Mbit x 16 organization, 133 mhz sdram chip. it accepts 3.3 volts + or - 0.3 volts. i used a multimeter and measured the voltage on the samsung chip, K4S641632k-uc75 and it gave me exactly 3.28 volts which is well within the memory's voltage tolerance.
i checked the back of the pcb to ensure that A12 is indeed connected to the broadcom cpu.
so yeah, i am pretty confident that all i have left to do is change some NVRAM variables to unlock the remaining 16 mb of ram.
I even have datasheets for both memory modules if anybody is interested.
This ram upgrade has solved so many problems for me, immediately, when going from 8 mb of flash to 16 mb of flash on DD-WRT V24 RC5, the ram usage jumped from the maximum it could use before (it was about 6 mb available, always used 92 to 97% of that) to 9944 kB used on 14452 kB available. this tells me that the router was runing with an insufficient amount of memory for dd-wrt. prior to the memory upgrade the router would crash and reboot if the amount of active ip connections exceeded roughly 650. The load average would also reach insane amounts of like 5.29 when there were alot of ip connections going on. now with the ram upgrade, load average does not exceed 0.30 at 1150 active ip connections. so this is good.
and i cant seem to get the router to tell me anything now after the ram upgrade when i use nvram show | grep sdram. i wonder why this is so.
so, to recap, i need help with unlocking the remaining 32 mb of ram, and this mod works on WRT 54g V8s (up to 16 mb for now)
datasheet.pdf
Description:
Datasheet for my 32 mb Mosel chip - not the exact same one, but its the same family, the specs apply to this one.
Chip was retrieved from Kingston KVR model KVR133X64C3/128 memory stick (pc133 for desktops)
my only problem is that i dont have a jtag or a serial cable to make one.
*edit* Its a parallel cable, not a serial cable*edit*
also, the chipset is not the same as older versions, this chipset is a BCM5354KFBG.
so im not sure if the old values apply to newer chipsets or if they are totally different.
the only thing keeping me from doing this is effectively the lack of a jtag and a lack of programming knowledge (so if i had one, i dont know what to do with it. hehe.)
Last edited by dragon-fly on Sun Dec 16, 2007 17:36; edited 1 time in total
my only problem is that i dont have a jtag or a serial cable to make one.
also, the chipset is not the same as older versions, this chipset is a BCM5354KFBG.
so im not sure if the old values apply to newer chipsets or if they are totally different.
the only thing keeping me from doing this is effectively the lack of a jtag and a lack of programming knowledge (so if i had one, i dont know what to do with it. hehe.)
they run off the same software the commands are the same. Im pretty sure that will enable the other 16 mb thus making it 32mb. and u dont have a jtag? wow ur pretty adventurous modifying the ram with out one lol
hehe i know, i dont have a heat gun or a jtag. totally awesome eh? :P
ill be tryng out those comands and i hope for the best.
only thing is that it doesnt seem like the same comands as those on another website. i get alot of conflicting comands for various versions, so i dont know which one to take :P
RolF wrote:
what sdram_init value you have now ?
R.
i cant say because nvram grep | whatever it was doesnt work anymore for some reason
alright, i tried it and i have a bricked router now.
now i get to find a parallel plug and make a jtag... more soldering...
i'll be needing help on how to recover it using a jtag....
and its bricked becaue the unit wont boot. it tries to boot but when it reads the ram it doesnt work (it freezes, the lan leds stay on)
referring to this, i believe i need the 0x000a and not the 0x0008 in sdram_init.
of course that is for a wrt 54 gl, which is why i dont know what to use. lol.
Hold the reset button and plug the power in keep holding it for 10 seconds should put it in flash recovery mode. and u can load the DDwrt firmware back on to it. go to http://192.168.1.1 and should be a white screen with just an option to update the FW. its definitly the NVram thats keeping it from booting so you should be able to ping it and tftp or use the browser to put the FW back on. and i beleive this resets the NVram as well.
try power off router, hold reset and then power on .
If tjis is not helping, then you must erase nvram with jtag.
And when you have working router read your original sdram_init value
the reset trick doesnt work, held it for more than 10 secconds to be sure, thats the first thing i tried when it wouldnt boot.
im pretty sure i need a jtag now. i already have half the stuff to make one at home, i found myself a paralel cable, and four 100 ohm resistors. all i need now is to find a way to plug the thing onto the router, so im probably going to solder on some connectors of sorts. i do hope the original JTAG for wrt 54gl applies to this router.
the router doesnt even let me ping it, so... windows doesnt even detect a connection, so forcing the ip would be futile
the reset trick doesnt work, held it for more than 10 secconds to be sure, thats the first thing i tried when it wouldnt boot.
im pretty sure i need a jtag now. i already have half the stuff to make one at home, i found myself a paralel cable, and four 100 ohm resistors. all i need now is to find a way to plug the thing onto the router, so im probably going to solder on some connectors of sorts. i do hope the original JTAG for wrt 54gl applies to this router.
the router doesnt even let me ping it, so... windows doesnt even detect a connection, so forcing the ip would be futile
thats not un common u have to set a static ip of 192.168.1.2 with a subnet of 255.255.255.0 and then set your NIC speed to 10 base t half duplex. then you might find that you can ping the router.
the reset trick doesnt work, held it for more than 10 secconds to be sure, thats the first thing i tried when it wouldnt boot.
im pretty sure i need a jtag now. i already have half the stuff to make one at home, i found myself a paralel cable, and four 100 ohm resistors. all i need now is to find a way to plug the thing onto the router, so im probably going to solder on some connectors of sorts. i do hope the original JTAG for wrt 54gl applies to this router.
the router doesnt even let me ping it, so... windows doesnt even detect a connection, so forcing the ip would be futile
thats not un common u have to set a static ip of 192.168.1.2 with a subnet of 255.255.255.0 and then set your NIC speed to 10 base t half duplex. then you might find that you can ping the router.
the pc doesnt even detect a network connection, let alone being able to ping the router.
i have a problem, the hairydairymain debrick tool doesnt support BCM 5354 (my chip), but it suports BCM 5352.
and also, i have no clue what i am supposed to input to get the nvram cleared.
i assume its going to be wrt54g -erase:nvram or something like that (do i include teh - or not?)
and if the tool doesnt work, is there another tool that supports WRT 54 g v8?
the reset trick doesnt work, held it for more than 10 secconds to be sure, thats the first thing i tried when it wouldnt boot.
im pretty sure i need a jtag now. i already have half the stuff to make one at home, i found myself a paralel cable, and four 100 ohm resistors. all i need now is to find a way to plug the thing onto the router, so im probably going to solder on some connectors of sorts. i do hope the original JTAG for wrt 54gl applies to this router.
the router doesnt even let me ping it, so... windows doesnt even detect a connection, so forcing the ip would be futile
thats not un common u have to set a static ip of 192.168.1.2 with a subnet of 255.255.255.0 and then set your NIC speed to 10 base t half duplex. then you might find that you can ping the router.
the pc doesnt even detect a network connection, let alone being able to ping the router.
i have a problem, the hairydairymain debrick tool doesnt support BCM 5354 (my chip), but it suports BCM 5352.
and also, i have no clue what i am supposed to input to get the nvram cleared.
i assume its going to be wrt54g -erase:nvram or something like that (do i include teh - or not?)
and if the tool doesnt work, is there another tool that supports WRT 54 g v8?
there is a sticky in this sub forum with the Jtag utility for v8 WRT54G routers i forgot bout that sorry. it has been modified for your Proc.