diff --git a/repo-installer/instgen.lua b/repo-installer/instgen.lua
index 8363a23..fd4579a 100644
--- a/repo-installer/instgen.lua
+++ b/repo-installer/instgen.lua
@@ -3,19 +3,67 @@ local serial = require "serialization"
 local tArgs = {...}
 local src, dest = tArgs[1], tArgs[2].."/"
 
-os.execute("mkdir "..dest.."/master/")
-os.execute("wget "..src.." -O "..dest.."/master/programs.cfg")
+local _OSVERSION = _OSVERSION or ""
+
+local function normalisePath(path)
+ local pt = {}
+ for seg in path:gmatch("[^/]+") do
+  pt[#pt+1] = seg
+ end
+ pre = ""
+ if path:sub(1,1) == "/" then
+  pre = "/"
+ end
+ return pre .. table.concat(pt, "/")
+end
+
+local function wget(src,dest)
+ dest=normalisePath(dest)
+ local fstr = "wget '%s' -qO '%s'"
+ local command = string.format(fstr,src,dest)
+ print(command)
+ return os.execute(command)
+end
+
+local dirs = {}
+local function mkdir(path)
+ path=normalisePath(path)
+ if dirs[path] then return true end
+ local fstr = "mkdir -p '%s'"
+ if _OSVERSION:sub(1,6) == "OpenOS" then
+  fstr = "mkdir -p '%s'"
+ end
+ local command = string.format(fstr,path)
+ print(command)
+ dirs[path] = true
+ return os.execute(command)
+end
+
+local function parsecfg(path)
+ path=normalisePath(path)
+ local f = io.open(path,"rb")
+ if not f then error("unable to open "..tostring(path).." for parsing") end
+ local rt = serial.unserialize(f:read("*a"))
+ f:close()
+ if type(rt) ~= "table" then error("unable to parse "..tostring(path)) end
+ return rt
+end
+local function writecfg(t,path)
+ path=normalisePath(path)
+ local f = io.open(path, "wb")
+ if not f then error("unable to open "..tostring(path).." for writing") end
+ f:write(serial.serialize(t))
+ f:close()
+end
 
 local pathpre = src:match("(.+/).+/.+")
 print(pathpre)
 
-local f = io.open(dest.."/master/programs.cfg","rb")
-if not f then
- print("Unable to open programs.cfg")
- return false
-end
-local programs = serial.unserialize(f:read("*a"))
-f:close()
+mkdir(dest.."/master/")
+local pcfgname = os.tmpname()
+wget(src,pcfgname)
+local programs = parsecfg(pcfgname)
+os.execute("rm '"..pcfgname.."'")
 
 local dlfiles = {}
 for k,v in pairs(programs) do
@@ -29,14 +77,23 @@ end
 for k,v in pairs(dlfiles) do
  local path,fn = v:match("(.+)/(.+)")
  if v:sub(1,4) ~= "http" then
-  os.execute("mkdir -p "..dest..path)
-  os.execute("wget "..pathpre..v.." -O "..dest..v)
-  print("wget "..pathpre..v.." -O "..dest..v..">/dev/null")
+  mkdir(dest..path)
+  wget(pathpre..v,dest..v)
  else
-  os.execute("mkdir -p "..dest.."/external")
-  print("wget "..v.." -O "..dest.."/external/"..v)
-  os.execute("wget "..v.." -O "..dest.."/external/"..fn.."> /dev/null")
+  mkdir(dest.."/external")
+  wget(v,dest.."/external/"..fn)
  end
 end
 
-os.execute("wget https://git.shadowkat.net/izaya/OC-misc/raw/branch/master/repo-installer/repoinstaller.lua -O "..dest.."/.install")
+-- merge programs.cfg with existing if applicable
+
+local w, oprograms = pcall(parsecfg, dest.."/master/programs.cfg")
+if w then
+ for k,v in pairs(oprograms) do
+  programs[k] = programs[k] or v
+ end
+end
+
+writecfg(programs, dest.."/master/programs.cfg")
+
+wget("https://git.shadowkat.net/izaya/OC-misc/raw/branch/master/repo-installer/repoinstaller.lua", dest.."/.install")