You can try updating via Crash Recovery mentioned by KaliBreizh:
D-Link forum wrote:
3. You cannot load the DD-WRT firmware through the D-Link GUI. You will have to do a crash recovery.
. Hold the reset button down.
. While still holding the reset button down, press the power button (to turn the router off) for 5 seconds and then press the button again to turn the router on while still holding down the button. You can also pull the power plug out and back in instead of using the power button.
. Wait 10 seconds and then release. Allow about 90 seconds for the router to boot. The power LED will blink red.
4. You will need to statically assign your computer an IP address of 192.168.0.2 (255.255.255.0).
5. Open Internet Explorer (do not use chrome, firefox, or edge). Go to http://192.168.0.1. The D-Link recovery page will appear. If it doesn't, you did not do the crash recovery properly. Repeat the process.
6. Browse to factory-to-ddwrt.bin file and click Upload.
7. Upgrade process should take 3-5 minutes.
8. When the success page appears, close your browser.
9. Change your IP settings on your computer to either DHCP or statically assign to 192.168.1.xxx (255.255.255.0). The default IP of the router will be 192.168.1.1.
10. Open Internet Explorer and enter 192.168.1.1. DD-WRT will now be installed. You will be prompted to create a username and password.
11. You can now upgrade the DD-WRT firmware (dlink-dir882-webflash.bin). Go to Administration > Firmware Upgrade and browse to the "webflash.bin" file.
To go back to the D-Link firmware, download the latest firmware from support.dlink.com/dir-882-us. The current is 1.10 which contains 2 firmware files - 1.04 and 1.10.
Perform a crash recovery on the router. Load the 1.04 firmware first. Once completed, log in to the router (192.168.0.1 username = admin password = leave blank). You will be prompted to update the firmware to 1.1 (1.10). Do that or you can upgrade to 1.10 manually.