I just bought a new one but it's version 4.21 and running this stock firmware:
Firmware Version: 3.12.11 Build 120320 Rel.50684n
Hardware Version: WR741ND v4 00000000
There is a warning in the download page saying this firmware cannot be downgraded.
I have tried Gargoyle factory, Openwrt and DD-WRT firmwares ,absolutely no luck with any of them.
I don't whant to open the router to use serial.
Can some one give me some hints.
Thanks
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[EDIT]
After several failures and hours of reading about possible solution i finally did it !
I was able to upload the factory firmware of gargoyle, but only version 1.5.7 and after renaming it to the same name of the current firmware of the device "wr741nv4_en_3_12_11_up(120320).bin".
I tried 1.5.9 and 1.5.8 with the default name of file and renamed to the original firmware name "wr741nv4_en_3_12_11_up(120320).bin", but allways got and error.
Its working ok so far, no reboots or gliches.
Hope this helps some of you.
Remember version 4.2 is newer than 4.3 as stated in some forums i read.
TP-link did no follow the normal numbering on this device it released first 4.3 and only after the 4.2 version.