try this instead

install.lua

@@ -56,7 +56,7 @@ local function main()
       toDownload[#toDownload+1] = v
     else
       local destfile = fs.open(v.dest, "r")
-      local filehash = hash.sha256(destfile.readAll())
+      local filehash = hash.sha256(destfile.readAll() .. "\n") -- newline is weird hack because of awkward hashes
       destfile.close()
       if filehash ~= v.sha256 then
         toDownload[#toDownload+1] = v

src/startup.lua

@@ -1,2 +1 @@
 print("Hello, World!")
-