Low Cost 24/7 LTE Failover/Failback Solution

pete_c said:
Just an FYI there elvisimprsntr relating to your endeavor.
It's been a few years now that I have purchased a few cheapo imports here.
They were combo routers with one WAN port, one USB cellular stick port, 5 LAN port and included Wifi.
Most I spent on these combo routers at the time was around $20.
They did have WAN failover built in to the OS's and it worked just fine as I would play with them.  They were just too big.
I always stayed away from Linksys, LinksysCisco crap.  (except for the linux based Linksys WRT-54G).  That is me.
I have been writing about tinkering with the tiny travel routers with two network ports and USB an Openwrt on them.
These do the same in a 3" square box with OpenWRT.  Last endeavor was using a modded GL-iNet travel router.  Here added an RTC clock and 1 wire network, plus VPN. 
I have not goofed around with the little ZTE wireless device.  I did find some firmware for it that would enable the USB port access which would then provide me with both wireless and USB access to the internet. 
I was looking for what was hopefully a drop in solution, as I was not looking for a science project. I stayed away from USB LTE sticks for the simple reason that those require firmware support on the router side, thus limiting your options to only proven devices.  Going with an Ethernet based LTE modem seemed to eliminate that problem.    BTW, I am extremely please with the Netgear LB1120 LTE modem.  
The LRT224 and RV042(G) routers claim to offer all the capabilities I was looking for, with a couple of exceptions.  Everything seemed to be working until I tried to enable FW access rules.  I tried to get Linksys to refund my $, but they will not offer refunds on products which are still under warranty, which strangely the LRT224 has a lifetime warranty.  I did not save the original packaging to send it back to the company I purchased it from.  I guess I am stuck with.  If I can't get Linksys to fix the firmware, I guess I will just not use those features which cause problems.    
as I was not looking for a science project. I stayed away from USB LTE sticks for the simple reason that those require firmware support on the router side
NOT a science project as every Chinese router that comes with a USB port for using a USB 3G or 4G stick comes already with the firmware to almost every stick ever made.   This has been so now for many many years.
That said you are looking at these products for the first time so you wouldn't know this.
Netgear and Belkin products are also made in China.   Cisco bought Linksys then sold it to Belkin. 
Putting the Cisco name / Logo on Linksys didn't do anything for the piece of crap product that it was and still is.
Putting the Belkin name on Linksys won't do anything for the piece of crap the product is today.
Thanks for the history lesson. I'll get the admin to delete this thread since you seem to already know everything and it is of no value to others.  This forum is of no use to me anymore.  I'm out!
Please continue with your endeavor. 
I didn't mean to hurt your feelings or be offensive. 
Your posts will help others looking to do the same with an off the shelf product.
BTW you can delete your original forum post topic using the moderate topic button.
At high risk of being berated by @pete_c, I'm (temporarily) back by request.
After exhausting all efforts to get Linksys to fix the LRT224 firmware, I broke down a picked up an "Essential" SFF router from http://protectli.com which has pfSense pre-installed.   After a bit of trial of error, and some tips from very helpful members at the UDI forum, I was able to get pfSense configured to finally get 24/7 LTE failover w/LAN IP limiting.  
Rather than re-post here, you can head over to the UDI forum for more info. http://forum.universal-devices.com/topic/21113-backup-isp-via-cellular/page-1
If Linksys balks at a manufacturers refund, I likely put the LRT224 up on eBay,  Although, using it for target practice might be more fun.  
I don't think Pete meant to berate you.  It's easy to read in to what someone says and take it personally.