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[edit] How To Flash

[Comment --n8hfi: On a very old WRT54G v1.0, I found it necessary to upgrade with a newer Linksys firmware before I could load DD-WRT. The original firmware (Linksys v1.00.8 Dec 24 2002) gave a 'incorrect image file' error on on both the mini and standard DD-WRT v23 SP2 images. The sequence that worked was (all done with the web GUI and-ugh-IE):

1. Restore factory defaults with the original firmware.
2. Upgrade to Linksys firmware version 4.21.1. You can get it here. Read the fine print carefully, not all firmware versions work with all hardware versions.
3. Then upgrade to DD-WRT v23sp2_mini_generic. I got the Continue page, but never got the DD-WRT GUI.
4. Hold the reset button for 30 seconds (I didn't cycle power or anything else on the router.)
5. Then I got the DD_WRT GUI. I reset it to factory defaults with the GUI, although this step may have been unnecessary, since I'd just flashed it.
6. Then I upgraded to DD-WRT v23sp2_standard_generic. I selected the 'restore factory defaults after flashing' option while doing this.
7. all set [Comment from jas3 on 16-Mar-2008: The above worked for me. I then updated from standard to dd-wrt.v23_vpn_generic.bin which succeeded as well]
8. May08, When upgrading to v24, please do a full firmware reset (hold reset button for 30 seconds on power up). I did not do this when upgrading to v24 and was getting all sorts of strange behaviors from my router. After resetting and then reconfiguring the router, all was well.

[edit] Other Notes

[dgb: 2009.04.25 V1.0 hardware with 1.02.1 firmware] On a V1.0 box with firmware 1.02.1 Feb 2003... First there is no administration tab, look under "system". With IE and eventually with Firefox pushing the Upgrade button resulted in a chooser (browser). I choose the dd-wrt bin file and pushed the Upgrade button, the browsers each failed. IE reported the server was busy or not available. Firefox sent a dump off to microsoft. So I located and tried to install a newer linksys firmware load - same results. I then loaded up netscape, turned off the blockers, configured it to open popups in a new tab, choose the newer linksys firmware and pressed update. It showed a progress bar as the firmware was loaded into the vintage box, Eventually the page went blank on "http://192.168.1.1/upgrade.cgi". Lights occasionally flicker as I impatiently wait and document the differences I've seen to this point.

I now have linksys FW revision v4.21.1 and an Administration tab...30/30/30

Still using NS and under Adminstration/Firmware Upgrade I selected the dd-wrt load dd-wrt.v24-9517_vint_voip, an upload progress bar displayed followed by "upgrade are failed!", I choose continue... Repeating the process has the same result. Third attempt, this time with IE - same result. I surmise that the router is not actually attempting to flash itself, but failing the .bin file. This for two reasons, the progress bar never gets much past 50% and the router never 'goes away", in fact it reports and error and wants to continue. The progress bar actually completes once then starts again before the failure notice.

Now I'm guessing here, but maybe some sick firmware developer who wasn't even in college when v1.0 hardware was available coded in an assert that the .bin file must be able to fit within the smaller modern architectures. I used IE to get the linksys firware to use dd-wrt.v24-9517_VINT_mini and "Upgrade is successful" from the unit. Pressed "continue" presented root/admin and here's my old friend dd-wrt! I can feel a new wireless bridge being born... 30/30/30 more Scotch, more beer.

Still using IE and using the dd-wrt upgraded to the desired ...voip load I wanted all a long. 30/30/30...

The old box is now running dd-wrt v24(05/20/08)voip uptime 1 min. There probably isn't a lot of this old stuff out there so maybe this isn't of interest to anyone else - but if you're trying, get netscape for that first giant step... [end dgb]

From DD-WRT Wiki

[edit] How To Flash

Install Instructions M. Mikowski on 26 Jan 2009 for WRT54Gv2 though web GUI, using Firefox on Linux. This is very similar to below, but with generic standard build using v24sp1. Notice the check of wl0_correv (step 5) before proceeding with full generic binary!

1. Perform 30/30/30 hard reset with the Linksys original firmware.
2. Upgraded to latest Linksys firmware (in my case, version 4.21.1). ( http://www.linksys.com/servlet/Satellite?c=L_CASupport_C2&childpagename=US%2FLayout&cid=1166859837401&pagename=Linksys%2FCommon%2FVisitorWrapper&lid=3740141396B08&displaypage=download#versiondetail ) select version 2 from drop down menu
3. Upgraded through the web firmware interface to dd-wrt.v24_micro_generic.bin from http://www.dd-wrt.com/dd-wrtv2/down.php?path=downloads%2Fstable%2Fdd-wrt.v24+SP1%2FConsumer%2FLinksys%2FWRT54G_v2/
4. Perform 30/30/30 hard reset. Web interface then becomes available via HTTP only (HTTPS was turned off). It asked me for a new username/password combination. After updating this info, the interface was accessible.
5. Confirmed from diagnostics that wl0_correv > 5 by going to http://192.168.1.1/Diagnostics.asp and typing in the Commands textarea "nvram get wl0_corerev" which returned "7". Per http://www.dd-wrt.com/wiki/index.php/What_is_DD-WRT%3F this means the standard build should be used.
6. Upgraded through the firmware web interface to dd-wrt.v24_std_generic.bin from http://www.dd-wrt.com/dd-wrtv2/down.php?path=downloads%2Fstable%2Fdd-wrt.v24+SP1%2FConsumer%2FLinksys%2FWRT54G_v2/

• --Plamoni 17:37, 18 July 2009 (CEST) - Note: Upgrade does not work using Safari. If you're using a Mac, use Firefox instead. Worked fine after that.
• Settings tend to apply well in IE 8 instead of Firefox 3.5.1. - 20/7/2009

Install Instructions Bualdoot on 12-Dec-2008: Install using instructions below. This is what I did and it worked like a charm. Very easy. No problems (all done with the web GUI and IE7):

1. Perform 30/30/30 hard reset with the Linksys original firmware.
2. Upgrade to Linksys firmware version 4.21.1. ( http://www.linksys.com/servlet/Satellite?c=L_CASupport_C2&childpagename=US%2FLayout&cid=1166859837401&pagename=Linksys%2FCommon%2FVisitorWrapper&lid=3740141396B08&displaypage=download#versiondetail ) select version 2 from drop down menu
3. Then upgrade to DD-WRT dd-wrt.v24-9517_VINT_mini.bin. I got the Continue page, clicked continue, got the login popup, entered root//admin for user//pass, then got the DD-WRT GUI!
4. Hold the reset button for 30 seconds (I didn't cycle power or anything else on the router.)
5. Then I upgraded to DD-WRT dd-wrt.v24-9517_VINT_std.bin. I selected the 'restore factory defaults after flashing' option while doing this.
6. After that, change your password and username and Router Name, if you want, and set all your other settings.

[edit] Other Notes

Comment Bualdoot on 12-Dec-2008: The comments below are from before I added the install instructions above. The comment below was refering to a comment that i removed, because it talked about not being sure if the WRT54Gv2 had more than 2MB memory, which of course we know it does. As for the instructions it gave that he refers to, they were not very clear, so, I made my own set of instructions based off the v1-v1.1 instructions.

all set [Comment from jas3 on 16-Mar-2008: The above worked for me. I then updated from standard to dd-wrt.v23_vpn_generic.bin which succeeded