HELP ME Please ! No Blue Lights on both of my WRTU54G-TM Routers behind a WRT54GX2 Router

Question

I've had this configuration installed and working for the past two months as such:
Motorola Cable Modem - COX Cable ISP - 15Mbps down / 5Mbps up ; actual rated is higher on speedtest.net
Linksys Router - WRT54GX2 (I'll refer to this as main Router)
Linksys T-Mobile Router - WRTU54G-TM - with 2 SIM cards (this is VOIP router 2 for two lines)
Linksys T-Mobile Router - WRTU54G-TM - with 1 SIM card (this is VOIP router 1 for one line)
Network Topology:
Main Router:     192.168.2.1    router mode ;  DHCP ON; Wireless ON - SSID: alpha
VOIP Router 2:  192.168.2.2   bridged mode; DHCP off; Wireless ON - SSID: beta
VOIP Router 1:  192.168.2.3   bridged mode; DHCP off: Wireless off
Both VOIP Routers connected from Internet Port on Router to LAN port on a 10/100 switch
All of this was working fine for the past two months, it even survived some Southern California power outages and came back with flying colors; UNTIL YESTERDAY...... VOIP Router 1 blue light ceased in the morning - Troubleshot it myself and then with tmobile/Linksys and verdict was a defective modem.  VOIP Router 2 was still going strong UNTIL I decided to power cycle it to see if that would help with VOIP Router 1; well the blue lights never came back on;  To make a long story short - after pulling my hair out and talking to tmobile/Linksys again; I was able to get the blue lights to come on both VOIP Router 1 and VOIP Router 2 if I connected one of them directly to the cable modem and the other VOIP Router  2 directly to VOIP Router 1.  I also did a hard reset on both VOIP routers back to factory defaults (did this before as well). Now,  I can't even have a switch between VOIP ROUTER 1 and 2 and get a blue light on the second one.  What in the world could be causing this, does anyone have a clue? 
Now you may ask why do I need it setup like I had it originally, Cable Modem is downstairs ; Main Router downstairs was in place to isolate the Network from the VOIP Routers in case I needed to reboot the VOIP routers - which I had to do a few times in those two months. So I still had Internet access in the house when I rebooted the VOIP routers.  I also wanted my phones upstairs, not downstairs and that is where the VOIP routers were situated.
I've searched thru this forum and googled elsewhere, but haven't found any solutions that work. 
So can anybody help ?????  TIA

Answer 1

OK, Here's an UPDATE, I believe that I have found a firmware bug in the WRTU54G-TM  v1.00.21 code.
In order to get the blue lights on two WRTU54G-TM Routers, VPN - IPSEC passthru must be enabled on the 1st Router, or else the blue lights will not come on the 2nd Router.   
fyi...  I have 3 sim cards in the 2 Routers for 3 phone lines, 1 Sim card slot is empty. 
I reset both WRTU54G-TM Routers to factory default and plugged one  directly in to the cable modem and the second WRTU54G-TM into the first.  I rebooted the cable modem and routers in order and in a few minutes, I had 3 blue lights for voice on the routers (YES!).  Ok, so now I tried reconfiguring the Routers the way I want them.  I only need wireless on one of them, not both, so I turn off the wireless on the first router, I also disable all 3 VPN passthrough options on both routers and disable the firewall on the 2nd router.  Now I lose the blue lights on the 2nd Router.   Well after some troubleshooting, I have found that the IPSEC VPN passthru option MUST be enabled on the 1st Router to get the blue lights on the 2nd Router.  I have reproduced this very easily by disabling the IPSEC on the first Router and the blue lights will go off on the 2nd Router -  I have to re-enable the IPSEC on the 1st router and reboot the 2nd Router for the blue lights to come back on the 2nd Router.    
Thanks, Tom  
(Mod note: Edited post for guideline compliance. Thanks!)
Message Edited by JOHNDOE_06 on 09-16-2009 01:08 PM