Upgrade from DD-WRT follow your instruction above. 5G works fine, but without 2.4G available.
And I restore all to factory in Tomato (Clear NVRAM, though mode), then it result in wireless lost (no wireless device and configuration could be found in Tomato).
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Update: I reboot it and 2.4/5G wifi did appear. It seems no problem now.
Thanks Shibby's great Tomato in Netgear R7000.
<------ THIS PROBLEM WAS IN THE YOUTUBE VIDEO FROM SHIBBY (7:40)
;D