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

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