Pi4 did not boot: Message start.elf: is not compatible 0x0

Hi everyone. i have 2 Raspberry PI4. The 4GB Version runs well and all is good. but my 2GB Version will not boot. i did the same as i did with the 4GB Version. First i use Etcher to write the 400MB Image file to an SD Card than i will boot it up with the pi but than. i only see the start screen with a error:
start.elf: is not compatible 0x0
Anyone knows that problem?
Thanks and Kind Regards

Nightly build fixes this problem.

I can confirm nightly build 2020-12-15 boot fine