I have been running LEDE 17 for a year or so ,I thought I would upgrade to OpenWrt 18 downloaded the sysupgrade file and looked for Sha file to confirm the integrity but can't find it. It seems to be far harder than it needs to be.I tried the script unfortunately it doesn't know whether it is Download.sh or download.sh but either way the sysupgrade target file gives an error " the file has no length" any ideas.
thanks