Prerequisite
1) Putty
2) WinSCP
3) Download the older stable ddwrt build. (https://download1.dd-wrt.com/dd-wrtv2/downloads/betas/2018/08-09-2018-r36527/dlink-dir882-a1/factory-to-ddwrt.bin) There are some stable build in May, 2020 based on the forum, pls check ddwrt forum if you decide to use ddwrt firmware rather than padavan.
4) Download a copy of breed.bin. I find the link below is still working.
https://pan.baidu.com/s/1FH5pEl5VLKHRhzSzh7E1PA#list/path=%2F
5) Download a copy of padavan firmware for DIR882 (Thanks hanwckf) I prefer to use one prepared by hanwcfk. Fewer addon and the English translation in the GUI is done well.
https://github.com/hanwckf/rt-n56u/releases
6) There is always a risk to load 3rd party custom firmware on the router. It is not supported by the vendor. Do it at your own risk!
7) I don't find an English version of breed.bin. That may be a problem because it only displays in Chinese. You will need someone who know Chinese to complete step 17-19. As you can see from the screenshot, it is displayed in Chinese.
Update steps
1) Power off the router (there is a power button from the back)
2) Use a toothpick to press the reset hole
3) Power on the router. Wait for 10s and release the toothpick
4) Connect your desktop to LAN1 of the router
5) Change your desktop NIC IP to 192.168.0.11, subnet mask to 255.255.255.0 and Primary DNS to 192.168.0.1
6) Connect the browser (try to avoid Firefox) to 192.168.0.1.
7) Upload the ddwrt firmware and wait for it complete. Always pick the factory-to-ddwrt.bin if the router is on D-LINK firmware.
8) Change the desktop NIC IP to 192.168.1.11
9) Connect the browser to 192.168.1.1
10) Change the login and password from ddwrt GUI. If you decide to use ddwrt firmware, you can stop here.
11) Go to Service, enable Secure Shell. Also make sure password login under Secure Shell is enabled. Save the settings
12) Now, SSH to 192.168.1.1. Run the command cat /proc/mtd
13) Depending on the output, backup all the mtd# to /tmp
In my case, I have mtd0 to mtd6
Then, I run the commands below
dd if=/dev/mtd0 of=/tmp/u-boot.bin
dd if=/dev/mtd1 of=/tmp/u-boot-env.bin
...............................................
14) Use WinSCP to copy the backup (step 13) in /tmp of router to your computer. Then, delete all the backup (step 13) in /tmp.
15) Copy breed.bin from desktop to /tmp of router
16) Then run the command below from putty.
cd /tmp
chmod 755 mtd-write
mtd -r write breed.bin u-boot
18) Select firmware backup then, EEPROM. Save a copy on your local computer.
19) Select firmware update. Then select the padavan firmware for the DIR882 from your desktop. Then click upload.
20) Change the NIC to obtain IP and DNS auto. Then, point to browser to 192.168.123.1 with credential admin/admin
21) Change the GUI to English. First click on the Firmware version link found at the top right.
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5/27 Checking hanwckf firmware link for all the issue. Looks like MU-MIMO is not supported if channel bandwidth is running at 160MHz.
https://github.com/hanwckf/rt-n56u/issues/319
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6/15 Running very stable since end of May.
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In router's web GUI, simply go
to menu path Administration --> Console and issue the following two commands,
clicking the Refresh button right after typing each one:
nvram set detectWan=0
nvram commit