[U-Boot] FDT retrived varaibles appear to have different properties fom other u-boot variables

[dh at synoia.com]

I have retrieved a string  "fdt get value bootargs /chosen bootargs" 

But, when I try "setenv a $bootargs" I get the error message:
setenv [-f] name value...
Is appears the variable set by the "fdt get" command hasdifferent properties from a u-boot variable where the content are available with $ operator.
The string variables retrieved with the fdt command appear to have different properties then strings in the u-boot variables. 

I can printenv bootargs, I cannot append to it by 
setenv ip ip=102.168.1.97
"setenv a $bootargs $ip"

Is this by design or is it a bug?

Duncan Hare

714 931 7952