-> https://openwrt.org/toh/western_digital/my_net_n750
-> https://downloads.openwrt.org/releases/21.02.3/targets/ath79/generic/openwrt-21.02.3-ath79-generic-wd_mynet-n750-squashfs-sysupgrade.bin
The file from the link above has f***ed up my Western Digital N750 - so how to restore it, it boots in an endless loop...
Thank you for your feedbacks.
Hi.
Have your read this line?
Warning: 21.02 release does not work. (March 2022). See owrt forum
You also have instructions to restore the device
' Warning: 21.02 release does not work. (March 2022)'
21.02.2 was working, that text is useless...
You can restore the original firmware from the manufactor, so the device will be in a safe state. Than you can install back OpenWrt, with a factory image.
You could try current master (snapshot) instead of 21.02.x
Baldulesia’s advice is correct. I own two of theses devices and if you follow those steps you should have no issue installing either 21 or 22.
I also have two of these devices, one i can't update - because it's in use with v19.x and i can't shut down / disconnect it. Because of that, it (currently) still runs with v19.x...
The other one i upgrade from 21.x to 21.02.x ca. 2 weeks ago. Then i was broken. After that, i used the recovery console - press reset button, then power on while hold reset button for a half minute... after that, it boots into a recovery console with ip 192.168.1.1 - but not DHCP so i need to give my PC a static IP e.g. 192.168.1.111. Then i recovered it with the firmware from Western Digital (which is available in an .iso file on Western Digital N750 download section. [Firmware Version is 16.04 or something like that when i remember right] After that, it was working correctly [at least on the first view] - and with the factory firmware, i was able to flash it again with that "problematic" OpenWRT 21.02.x release - with the full (not "systeupgrade") OpenWRT firmware file... but a few days ago, it seems it has destroyed itself. I don't know why. I think there are some "traces" due to my actions i've done with...?
And: So i saw, currently are more of these N750 devices available e.g. on eBay and other auction portable - maybe because many other people bricked it as same as i've done and then sell it in that (broken) condition. (yes, i've bougth a defect one from eBay england [no DHCP, no Web GUI, seems to reboot which i see on network adapter disconnects on OS] which is also able to boot into the recovery console, but that one does NOT accept the factory firmware file anymore...)
Yes, so it seems it's possible to brick them in an irreversible way - at least i.m.o.
Hi there
How the 22.x version was released: https://openwrt.org/toh/western_digital/my_net_n750
Has somebody any experiences with that version on Western Digital N750?
Thank you very very much for your feedback(s)... 
Version 22 will install and works on a WD N750. Unfortunately it is only a matter of time (a day to a few weeks) until the SquashFS corruption issue will appear and the router will ultimately become unstable and crash. This does not occur on 19.07.
More details here:
I have been flashing images that I create from the firmware selector, especially if I need to add extra packages.
If I change a config, I edit the backup and re-upload it in whole.
This is the only means I don't have corruptions, loose WiFi, etc.
I've only been able to use a WD N750 with version 21 and above with minimal configs and no added packages. Version 19 was version that didn't present these kinds of issues.
Hope this helps.
Reference of a few issues in different threads: https://forum.openwrt.org/search?q=n750%20%40lleachii%20order%3Alatest
Hi there
Does somebody have a custom-compiled OpenWRT version > 19.x where these problems are fixed?
If yes, can i download them somewhere?
Thank you very much for your feedback(s).
Thank you very much - but i was thinking the 19.x version was always running WITHOUT any problems? Or has the 19.07.10 version (non-custom) OpenWRT also problems on the WD N750? Because of that a special version of OpenWRT 19.07.10 for the N750...?
Has the 19.07.10 version some WPA3 support...? That's what i espcially need...
Why i should download the OpenWRT v19.07.10 from https://firmware-selector.openwrt.org/?version=19.07.10&target=ath79%2Fgeneric&id=wd_mynet-n750 instead from [OpenWrt Wiki] Western Digital My Net N750 ??
Thank you very very much for your feedback(s)...
I don't think so. Or does WD say the My Net 750 has got WPA3-compliant hardware? Without the proper hardware, you won't get WPA3-support even if the driver offers it.
Edit:
According to https://openwrt.org/toh/hwdata/westerndigital/westerndigital_mynetn750, the device has been manufactured long (5 years) before WPA3 has been invented.
So, in my opinion the chances of WPA3-support are non-existent.
ar9344/ ar9380 (both ath9k) has no problems with WPA3/ SAE, it just works with modern OpenWrt (including hardware accelerated IEEE 802.11w) - your zoo of non-linux clients however might be more difficult.
In v21.x i had WPA3 support, by that version was not stable in other ways... 
I didn't knew that, on the other hand there aren't many informations available on the net. Thank you for the clarification.