From DD-WRT Wiki

 **NOTE**:  This Wiki is WIP

[edit] Hardware Specifications

[edit] Installation

 **WARNING**:  DO NOT PERFORM A 30/30/30 VIA RESET BUTTON
 **NOTE**:  SEE Where do I download firmware? for information on where to download firmware files.

[edit] Prerequisites

1. Download the factory-to-ddwrt.img and dd-wrt-webflash.bin files from the linksys-mx4200-v1 or linksys-mx4200-v2 folder as applicable.

[edit] Procedure

[edit] Via Linksys WebUI

1. Connect your PC via Ethernet cable to one of the LAN ports on the back of your router.
2. Launch/open a web browser and enter http://myrouter.local/ or http://192.168.1.1 in the address bar.
3. Click on the cell phone on the splash screen.



• A login page will display. Enter your Router Password and click Sign In.
• The default administrator password of an unconfigured router is admin. If you have changed it, enter the new password instead.



4. To enter into the support mode, click on the “CA” link and the bottom of the page.



5. Click Connectivity.



6. In the Firmware Update section, under the Basic tab, click the Choose File button.



7. Select the previously downloaded factory-to-ddwrt.img file and click Open.
8. Click the Start button. On the Update firmware pop-up box, click Yes.
• Your router will start updating the firmware.

 **CAUTION**:  After you start the firmware update, do not try to go online, turn off or do anything else to the router, or close the browser window until it finishes restarting.

9. In your browser, go to http://192.168.1.1
• You should be greeted by the password change page of the DD-WRT webUI.
10. Set username (optional, default username is root) and password (enter password twice, these *must* match and are case-sensitive).
• You should be greeted by the System Info page of the DD-WRT webUI
• SEE Upgrading DD-WRT section to flash the full version, then proceed to the following step.
11. Click on Setup to begin configuration to your needs.
• You will be required to enter username and password previously set.
12. Click Save on each page (unless otherwise noted in a specific tutorial).
13. When finished, Click on Services or Administration tab and click Reboot.

[edit] Via Hidden Manual Upgrade Page

1. Connect your PC via Ethernet cable to one of the LAN ports (Ethernet) on the back of your router.
2. Launch/open a web browser and enter https://192.168.1.1/fwupdate.html into the address bar in the browser.
• Depending on which browser you are using, you may come across an error.
• This error occurs when accessing a router that requires using an HTTPS connection.
• To bypass this window, follow these steps.
• You will be greeted by a login pop-up. Enter the credentials. Default user/password is admin/admin.
• You will be redirected to the hidden manual firmware upgrade page.



3. Enter “admin” as the default administrative router password.
4. Click on Select File and select the previously downloaded factory-to-ddwrt.img file and click Open.
5. Click Update.

 **CAUTION**:  After you start the firmware update, do not try to go online, turn off the router, or do anything else to the router until it finishes restarting.

6. In your browser, go to http://192.168.1.1
• You should be greeted by the password change page of the DD-WRT webUI.
7. Set username (optional, default username is root) and password (enter password twice, these *must* match and are case-sensitive).
• You should be greeted by the System Info page of the DD-WRT webUI
• SEE Upgrading DD-WRT section to flash the full version, then proceed to the following step.
8. Click on Setup to begin configuration to your needs.
• You will be required to enter username and password previously set.
9. Click Save on each page (unless otherwise noted in a specific tutorial).
10. When finished, Click on Services or Administration tab and click Reboot.

[edit] Upgrading DD-WRT

 **WARNING**:  DO NOT PERFORM A 30/30/30 VIA RESET BUTTON
 **NOTE**:  SEE Where do I download firmware? for information on where to download firmware files.

[edit] Prerequisites

1. Download the dd-wrt-webflash.bin file from the linksys-mx4200-v1 or linksys-mx4200-v2 folder as applicable.

[edit] Prodecure

 **NOTE**:  See model specific prerequisite info above first.
 **WARNING**:  Do not use this file to go from Stock to DD-WRT.
 **NOTE**:  Reset to defaults is recommended if you are upgrading from a very old build (> 6 months).
 **NOTE**:  Do not restore a backup from one version to another version of DD-WRT, as nvram variable names may have changed.

1. Connect your computer to your router with an Ethernet cable.
2. Open a web browser and navigate to http://192.168.1.1 (or whatever you set your router IP to).
3. Enter username and password as required.
4. Go to Administration -> Firmware Upgrade
• Leave Do Not Reset selected for After Flashing
5. Click on Browse and select the appropriate previously downloaded dd-wrt-webflash.bin file specific to your router model version.
6. Click Open
7. Click Upgrade
• The firmware update starts and the router restarts. The firmware update process takes about five minutes.

 **CAUTION**:  After you start the firmware update, do not try to go online, turn off the router, or do anything else to the router until it finishes restarting.

8. If the webUI does not automatically go back to the Setup -> Basic Setup page, or does not stop at the progress bar page to allow you to click Continue after waiting at least five minutes (i.e. if you get a "Connection Reset" or other error page in your browser), enter http://192.168.1.1 (or whatever your router IP address is) manually or click and hold the "Back" button and select the appropriate history entry.

[edit] Revert to Factory Firmware

 **NOTE**:  DD-WRT 58283 OR NEWER REQUIRED TO BE INSTALLED ON ROUTER.

1. Download the applicable OEM firmware image from MX4200, MX4200C, MX8000, MX8400C, MX12600 Downloads
2. Upload factory firmware .img file to the router's /tmp folder using an scp client.
3. SSH or Telnet into the router's console and cd to /tmp.
4. Do #ls -lart to make sure the file you just uploaded is present.
   • Using the -lart flags will sort your newly uploaded factory firmware file to the bottom of the output list.
5. Check to see which boot partition you are on by issuing:

   #fw_printenv -n boot_part

 **NOTE**:  If the file is not present when you run the following command, you will get a segmentation fault.

6. Flash factory image.
   • If the boot partition is 1, issue the following:

   mtd -e linux2 -f write factoryfilename.img linux2

   • If the boot partition is 2, issue the following:

   mtd -e linux -f write factoryfilename.img linux

 **NOTE**:  If you see this error, you can ignore it:

Warning unaligned data, we use manual padding to avoid errors. size was 131072!!!

7. Once completed you need to change your boot partition to where you just flashed the factory firmware.
   • If you flashed to linux2, then set it to 2; If you flashed it to linux, set it to 1.

   fw_setenv boot_part 1|2

 **NOTE**:  If you wish to flash both partitions via CLI, you may do so; or you can flash the other via Linksys WebUI after reboot.

8. Reboot.

[edit] Recovery

WIP

[edit] Serial Pinout

[edit] Links, Notes, and Further Reading

• MX4200 - Tri-Band AX4200 Mesh WiFi 6 Router
• MX4200, MX4200C, MX8000, MX8400C, MX12600 Downloads
• Linksys MX4200 - OpenWRT Wiki
• Soporte DD-WRT para Linksys MX4200?