Yesterday I flashed OpenWrt 19.07.0 on my ver.13 WR841N router using the TFTP method (original TP-Link firmware wasn't accepting the image even after renaming).
The OpenWrt seems pretty stable. Regarding the wireless - I configured the WR841N as a wireless client and connected it to my WR1043ND. The test were performed first in the same room and then in two different rooms (two brick walls appart) and so far everything seems fine with 19.07.0.
So here they are:
Test 1: Quick ping test (100.000 packets at 1000 pkt/sec.), same room (signal@WR841N -52 dBm)
[linux server] <---> [WR1043ND] ~~~ [WR841N(192.168.8.17)]
c0decrow@nmsz: ~ $ sudo ping -q -s 1500 -c 100000 -i 0.001 192.168.8.17
PING 192.168.8.17 (192.168.8.17) 1500(1528) bytes of data.
--- 192.168.8.17 ping statistics ---
100000 packets transmitted, 99990 received, 0% packet loss, time 167356ms
rtt min/avg/max/mdev = 1.013/1.639/28.993/0.870 ms, pipe 3
Graphing on WR1043ND shows about 7Mb/s traffic on wlan0:
Test2: Continuous ping test (10 hours), same room (signal@WR841N -52 dBm)
[linux server] <---> [WR1043ND] ~~~ [WR841N(192.168.8.17)]
c0decrow@nmsz: ~ $ ping -q -s 1500 -c 36000 192.168.8.17
PING 192.168.8.17 (192.168.8.17) 1500(1528) bytes of data.
--- 192.168.8.17 ping statistics ---
36000 packets transmitted, 35997 received, 0% packet loss, time 36051014ms
rtt min/avg/max/mdev = 1.183/1.823/53.937/1.033 ms
Test3: Quick ping test (100.000 packets at 1000 pkt/sec.), different room (signal@WR841N -72 dBm)
[linux server] <---> [WR1043ND] ~~~ [WR841N(192.168.8.17)]
c0decrow@nmsz: ~ $ sudo ping -q -s 1500 -c 100000 -i 0.001 192.168.8.17
PING 192.168.8.17 (192.168.8.17) 1500(1528) bytes of data.
--- 192.168.8.17 ping statistics ---
100000 packets transmitted, 99979 received, +3 errors, 0% packet loss, time 188135ms
rtt min/avg/max/mdev = 1.019/1.879/47.401/1.479 ms, pipe 16775
Test 4: Bandwidth test using two MikroTik routers and the two TP-Links between them(same room)
[MikroTik 1] <---> [WR1043ND] ~~~ [WR841N]<--->[MikroTik 2(192.168.8.3)]
First I'm testing both directions, then only Tx, about 70Mb/s troughput. There are some drops on the graph, but without packet loss:
Conclusion: The issue seems fixed.
Looks like that ver.13 with OpenWrt 19.07.0 will be the only version WR841N without the 4/32 problem.
I will deploy this router for real traffic soon so I will continue testing and let you know if some issues comes out.