diff --git a/sys/apis/fs/urlfs.lua b/sys/apis/fs/urlfs.lua
index 3ffd839..ef6d3ab 100644
--- a/sys/apis/fs/urlfs.lua
+++ b/sys/apis/fs/urlfs.lua
@@ -1,5 +1,4 @@
-local synchronized = require('sync')
-local Util         = require('util')
+local Util = require('util')
 
 local fs = _G.fs
 
@@ -51,9 +50,7 @@ function urlfs.open(node, fn, fl)
 
   local c = node.cache
   if not c then
-    synchronized(node.url, function()
-      c = Util.download(node.url)
-    end)
+    c = Util.httpGet(node.url)
     if c then
       node.cache = c
       node.size = #c
diff --git a/sys/apis/injector.lua b/sys/apis/injector.lua
index bd15e22..7e3f847 100644
--- a/sys/apis/injector.lua
+++ b/sys/apis/injector.lua
@@ -6,41 +6,53 @@ local fs   = _G.fs
 local http = _G.http
 local os   = _G.os
 
--- fix broken http get
-local syncLocks = { }
+if not http._patched then
+  -- fix broken http get
+  local syncLocks = { }
 
-local function sync(obj, fn)
-  local key = tostring(obj)
-  if syncLocks[key] then
-    local cos = tostring(coroutine.running())
-    table.insert(syncLocks[key], cos)
-    repeat
-      local _, co = os.pullEvent('sync_lock')
-    until co == cos
-  else
-    syncLocks[key] = { }
+  local function sync(obj, fn)
+    local key = tostring(obj)
+    if syncLocks[key] then
+      local cos = tostring(coroutine.running())
+      table.insert(syncLocks[key], cos)
+      repeat
+        local _, co = os.pullEvent('sync_lock')
+      until co == cos
+    else
+      syncLocks[key] = { }
+    end
+    local s, m = pcall(fn)
+    local co = table.remove(syncLocks[key], 1)
+    if co then
+      os.queueEvent('sync_lock', co)
+    else
+      syncLocks[key] = nil
+    end
+    if not s then
+      error(m)
+    end
   end
-  local s, m = pcall(fn)
-  local co = table.remove(syncLocks[key], 1)
-  if co then
-    os.queueEvent('sync_lock', co)
-  else
-    syncLocks[key] = nil
-  end
-  if not s then
-    error(m)
+
+  -- todo -- completely replace http.get with function that
+  -- checks for success on permanent redirects (minecraft 1.75 bug)
+
+  http._patched = http.get
+  function http.get(url, headers)
+    local s, m
+    sync(url, function()
+      s, m = http._patched(url, headers)
+    end)
+    return s, m
   end
 end
 
 local function loadUrl(url)
   local c
-  sync(url, function()
-    local h = http.get(url)
-    if h then
-      c = h.readAll()
-      h.close()
-    end
-  end)
+  local h = http.get(url)
+  if h then
+    c = h.readAll()
+    h.close()
+  end
   if c and #c > 0 then
     return c
   end
diff --git a/sys/apis/util.lua b/sys/apis/util.lua
index fda9ff0..cbde077 100644
--- a/sys/apis/util.lua
+++ b/sys/apis/util.lua
@@ -1,5 +1,11 @@
 local Util = { }
 
+local fs        = _G.fs
+local http      = _G.http
+local os        = _G.os
+local term      = _G.term
+local textutils = _G.textutils
+
 function Util.tryTimed(timeout, f, ...)
   local c = os.clock()
   repeat
@@ -12,7 +18,7 @@ end
 
 function Util.tryTimes(attempts, f, ...)
   local result
-  for i = 1, attempts do
+  for _ = 1, attempts do
     result = { f(...) }
     if result[1] then
       return unpack(result)
@@ -72,11 +78,11 @@ end
 function Util.getVersion()
   local version
 
-  if _CC_VERSION then
-    version = tonumber(_CC_VERSION:gmatch('[%d]+%.?[%d][%d]', '%1')())
+  if _G._CC_VERSION then
+    version = tonumber(_G._CC_VERSION:gmatch('[%d]+%.?[%d][%d]', '%1')())
   end
-  if not version and _HOST then
-    version = tonumber(_HOST:gmatch('[%d]+%.?[%d][%d]', '%1')())
+  if not version and _G._HOST then
+    version = tonumber(_G._HOST:gmatch('[%d]+%.?[%d][%d]', '%1')())
   end
 
   return version or 1.7
@@ -351,13 +357,18 @@ function Util.loadTable(fname)
 end
 
 --[[ loading and running functions ]] --
-function Util.download(url, filename)
-  local h = http.get(url)
-  if not h then
-    error('Failed to download ' .. url)
+function Util.httpGet(url, headers)
+  local h, msg = http.get(url, headers)
+  if h then
+    local contents = h.readAll()
+    h.close()
+    return contents
   end
-  local contents = h.readAll()
-  h.close()
+  return h, msg
+end
+
+function Util.download(url, filename)
+  local contents = Util.httpGet(url)
   if not contents then
     error('Failed to download ' .. url)
   end
@@ -418,8 +429,8 @@ function Util.toBytes(n)
   return tostring(n)
 end
 
-function Util.insertString(os, is, pos)
-  return os:sub(1, pos - 1) .. is .. os:sub(pos)
+function Util.insertString(str, istr, pos)
+  return str:sub(1, pos - 1) .. istr .. str:sub(pos)
 end
 
 function Util.split(str, pattern)
diff --git a/sys/network/snmp.lua b/sys/network/snmp.lua
index 04538d0..123993e 100644
--- a/sys/network/snmp.lua
+++ b/sys/network/snmp.lua
@@ -111,7 +111,6 @@ device.wireless_modem.open(999)
 print('discovery: listening on port 999')
 
 Event.on('modem_message', function(e, s, sport, id, info, distance)
-debug(info)
   if sport == 999 and tonumber(id) and type(info) == 'table' then
     if not network[id] then
       network[id] = { }
@@ -151,7 +150,6 @@ end
 
 -- every 10 seconds, send out this computer's info
 Event.onInterval(10, function()
-debug('timer')
   sendInfo()
   for _,c in pairs(_G.network) do
     local elapsed = os.clock()-c.timestamp