Any news on the porting effort? I also have an Archer MR400 (v4.9) and would like to use openwrt on this thing too.
I wont try anymore to it, if I am you. Cause this router only has 16M space flash rom, with so less storage space you can't even install a web ttyp application into.
And in the short future you will not able to find any new TPLink product in EU/US countries. Neither those IoT products which have backdoors surely by east big nation. Forget them bro.
16M is still sufficient for most OpenWrt images even with 25.12.
And one year later Tp-Link is still available in the EU... nothing terrible in using them with OpenWrt (you can even find custom bootloaders for some if you look hard enough, to clean them of "east big nation" code entirely).
Important side note: cross-flashing OEM Tp-Link firmwares between different models can break your modem, since the provided binaries usually also include the modem firmware updates in them. I know because I broke the modem on a MR6400v5 by playing with the wrong firmware versions (v5 / v5.2 / v5.3). Did you ever get the modem on that MR400 working again?
Nop the modem doesn't work anymore, it's damaged. I knew the risk, but the EU version modem doesn't work in US. So I don't mind it's broken. By the way, the 5Ghz wifi chip of MR400 is wared out after 1 year use.