Suitable for TP-Link TL-WR941ND v.5.2, and possibly for 5.0 (not tested)

If you want to modify the firmware yourself, do as follows:
 - Download (or build) openwrt-ar71xx-generic-tl-wr841n-v8-squashfs-factory.bin
 - Open it in a hex editor. Look at offset 0x40. There should be the following bytes: 08 41 00 08. Modify to: 09 41 00 05
 - Get mktplinkfw.c, md5.c and md5.h. Compile the tool: gcc -Os mktplinkfw.c md5.c -o mktplinkfw.
 - Run: ./mktplinkfw -i *-factory.bin
 - Look for the expected MD5Sum1: expected : e5 67 34 4d 04 99 20 60 f5 76 c6 04 15 81 ab f8
 - Open the hex editor again, go to offset 0x4c, and copy the MD5 above (it should span from offset 0x4c to offset 0x5b).
 - Go and upload the resulting file to firmware upgrade (in TP-Link web-interface). Good luck.

Source: https://forum.openwrt.org/viewtopic.php?id=44319