I have an E2500 v2 and I was able to successfully get Shibby 119 running on it.
The firmware that I installed:
The About Page says this:
Tomato Firmware 1.28.0000 MIPSR2-119 K26 USB Max
USB support integration and GUI,
Linux kernel 18.104.22.168 and Broadcom Wireless Driver 22.214.171.12412 updates,
support for additional router models, dual-band and Wireless-N mode.
Copyright (C) 2008-2011 Fedor Kozhevnikov, Ray Van Tassle, Wes Campaigne
I am wondering if you do one of those 30/30/30 resets, and then cable in to the router to see if the 5GHz radio is there.
If that does not work, maybe a reflash? Checksum your download too, just in case (I prefer the Microsoft tool FCIV for that).
I can see both the 2.4GHz and the 5.0GHz radios, and like JohnC, I did not initially have anything that could see the 5GHz SSID.
I picked up some Dual_N network cards and was good to go.
Just make sure that you enable the 5GHz:
Basic —> Network —> Wireless (5Ghz/eth2) —> Check Enable —> Save Button
I can't remember if I rebooted the router or not. But it has been up for several days now.
I hope this helps, I will check back often to see how it went for you.