My buddy Richard Skaggs is having all kinds of trouble with noise before and after the firmware update. He said going to see if Doug can resolve the issues.
Ricky Skaggs is your buddy? 
This is very familiar. I have had several (3 or more) of similar failures. They have mostly looked like this. However I had a couple in the ambient channels that didn't look weird, but had audible noise issues.
I have updated the firmware and switched from a 128 gig sdxc card to a 32 gig sdhc card. I purchased my unit from Oade Brothers. I am sending this into Doug to see if he can figure something out.
I can't depend on this device, and usually I do 4 channel for some promoter or festival or such. My Tascam dr60 has been rock solid. I will be utilizing this until I get something sorted out, even though I think this unit sounds better with the mods.
Richard