There is some confusing info in your post. you say you are using: Connect ME 9210 2M [DC-ME-01T-S]
But DC-ME-01T-S is not Connect ME 9210, it is regular Connect ME. and I suspect you are not using [DC-ME-01T-S] but using [DC-ME-01T-C]. Is this correct?
Netos 6.0 is extremely old and has been not supported for over 10 years. Would you consider upgrading your app to the latest version of netos?
Otherwise, do you still have netos 6.0 build system?
The first thing I would try is to use the same images on ME4 as it is the same hardware and just larger memory, but it might work as is. Do not update bootloader, just the application image unless you have a good reason to do so. Try it on a module with JTAG first so you can recover if it bricks.