Hello Mark,
it seems the tool chain is not the problem here. Another guess would be that your TCL interpreter or shell chokes on the respective exec statement in tool/run/image/uboot
set entrypoint [exec [cross_dev_prefix]readelf -h $elf_img | \ grep "Entry point address: " | \ sed -e "s/.*Entry point address: *//"]
Please try to apply the attached patch to find out if readelf could be executed individually.
Greets