Nvidia Shield Tablet "Insufficient memory" Error

I was reinstalling the 1.2.1 update to my Shield Tablet, which I have done several times before, and I received an error.
When I input “fastboot flash system system.img” , I get FAILED (remote: Insufficient memory.) I have a 16GB WiFi only US Tablet. The only thing that is different than the other times I did this process, is that I recently had Lollipop update on the tablet. Please help…

this is the scary part…
im stuck on the same process.
LTE USA nvidia tablet.
needed to downgrade my firmware since im having cellular problems with lolipop.
tried turning on my device. failed. stuck on bootloop

It is SCARY… I had to contact Nvidia and do an RMA… They tried to tell me that because I tried to downgrade the unit that I voided the warranty. Which is bogus, it was thier image… they finally agrred to send me another unit… A REFURBISHED one, but it works… I had my unit for only 3 months…

I noticed the smaller 639mb (Factory) 648mb (59) can install. the larger system images error out.

I have this same problem with a Shield Portable. I can only flash the two original .img files Factory and 59. Any other update errors out when attempting to flash the system.img I get an error remote: Insufficient Memory.

Attempting to let the system run the updates from Settings/About etc… it can attempt to update to version 103 but it will not complete the install and I end up with the new boot screen and it locks up.

Is this error limited to some specific original machines?

I don’t mind running an older build but I need GamePad Mapper support. I don’t thing the “Factory” or version 59 include it.