I have several DIR-885L routers, two A1s and three A2s. I've only just recently tried to install OpenWrt on any of them. I started by installing it on an A1, with which I'd recently started to have issues. Specifically, the 2.4Ghz and 5GHz stopped working. I figured if I bricked it, no big loss.
@panomitrius I've now flashed one of my A2s with OpenWrt 19.07.7 and immediately got the 2.4GHz radio configured and working. I'm using the (brcmfmac4366c-pcie) firmware suggested in the guide, and can confirm that no .txt file is required. Initially I had problems getting the 5Ghz radio to work. I found that it would switch to Client mode, even though it had been set to AP mode. The problem appeared to be associated with the Channel "auto" option. As soon as I selected Channel 44, it worked. I suggest not using the Channel "auto" option, and try different channels until you find one that works.
I've found that some of the 5GHz channels don't work. Once I have a complete list of what works, and doesn't, I'd like to file a bug report (if someone would kindly point me to the appropriate location).
@yfwwangyue As mentioned above, I started down this "rabbit hole" by flashing an A1 which had wireless issues. With OEM firmware installed neither radio worked. However, once I flashed it with OpenWrt, I got the 2.4GHz radio working. As you've only posted a portion of your logs, it's hard to see what's going on. However, if you're not getting the following message, it's likely a hardware problem. I'd suggest reverting to the OEM firmware to confirm that everything is working properly, then try flashing OpenWrt again.
pcie_iproc_bcma bcma0:8: link: UP