It is a big shame that such an expensive router didn't receive a new firmware version ever since 2017/9/12. Especially looking at all the problems with the wifi channels. Then, the maturity and quality of the replies (if any) by TP Link 'team' is the worst I have ever met. I am still having the problem that the second 5 ghz is disappearing . Or is there already a workaround about this ISSUE?

I also have this router and I have some serius issues with it!!!

5GHz signal keeps dissapearing, but the most annoying problem is Led controller error. each time it appears in log my connection to internet breaks and for most times I have to restart rouetr to get it connected. I dont know what is the problem and didnt find the solution. It is very bad policy for TP link not to have new update to this router in nearly two years. I will hold my nerves and use this for couple of weeks and will never buy anything from tp link (long time user and i recomended few dozens of their AP or routers to friends but never again)

if someone knows solution please respond or recomend some other router

thx

BYe

@AppieK1 

Firmware updates are only usually released when ther are enhancements or bugs in the software.  Some isuses may be hardware related and as such a firmware update may not be needed.  Also it could be that the version of that device has been deemed end of life.  When this happens firmware update are only made when crtitical issues are detected.  Again this is only if these issues are software related.  If your device is on the latest FW version and an channel keeps disappearing you might have defective hardware and if you are with in the warranty period a replacement can be issued.  You would want to contact support via Chat, Phone or email though so they can collect infromation about your product, verifiy warranty eligiblity and troubleshoot if nessasary.    US support can be reached here:  https://www.tp-link.com/us/support/contact-technical-support/

@edichu 

Your product is still covered for the legnth of the warranty.  If your product is end of life it will be replaced with a product of equilvant value or features.  

@kenhwa More than 1 year later and that issue still persists :(

@hantuonline How was your problem solved? I have the same issue now.

@PeterAmant i claimed warranty. Apprarently it was a defective firmware update that caused it. I am not updating the firmware in the replacement unit.

@edichu 

So is that really the solution recommended by tp-link support? Not to update the device with their latest firmware because it´s not working properly...?

I bought an Archer C5400 a couple of months ago, unpacked and installed (including updating to the latest firmware), and no wi-fi channel worked at all after that.... RMA from the retailer and now got a new one. 

Loads of people in this thread with simular issues and seems pretty unstable to update to the latest firmware so I understand. On the other hand there are some "critical" bug-fixes in that latest built and some desireble new features what I can see? 

Does your device working properly now despite that you didn´t update firmware?