diff --git a/sys/extensions/3.netdaemon.lua b/sys/apps/netdaemon.lua
similarity index 97%
rename from sys/extensions/3.netdaemon.lua
rename to sys/apps/netdaemon.lua
index 7e3ef77..0a5a78d 100644
--- a/sys/extensions/3.netdaemon.lua
+++ b/sys/apps/netdaemon.lua
@@ -3,8 +3,6 @@ _G.requireInjector()
 local Event = require('event')
 local Util  = require('util')
 
-_G.network = { }
-
 local device     = _G.device
 local fs         = _G.fs
 local network    = _G.network
diff --git a/sys/boot/opus.boot b/sys/boot/opus.boot
index ef1c8eb..716b848 100644
--- a/sys/boot/opus.boot
+++ b/sys/boot/opus.boot
@@ -3,7 +3,6 @@ local colors = _G.colors
 local fs     = _G.fs
 local http   = _G.http
 local os     = _G.os
-local shell  = _ENV.shell
 local term   = _G.term
 local window = _G.window
 
@@ -16,6 +15,8 @@ for k,v in pairs(_ENV) do
   sandboxEnv[k] = v
 end
 sandboxEnv.multishell = { }
+sandboxEnv.BRANCH = BRANCH
+sandboxEnv.LUA_PATH = 'sys/apis:usr/apis'
 
 _G.debug = function() end
 
@@ -64,24 +65,6 @@ local function splash()
   return splashWindow
 end
 
-local function setLabel()
-  -- Default label
-  if not os.getComputerLabel() then
-    showStatus('Setting computer label')
-
-    local id = os.getComputerID()
-    if _G.turtle then
-      os.setComputerLabel('turtle_' .. id)
-    elseif _G.pocket then
-      os.setComputerLabel('pocket_' .. id)
-    elseif _G.commands then
-      os.setComputerLabel('command_' .. id)
-    else
-      os.setComputerLabel('computer_' .. id)
-    end
-  end
-end
-
 local function makeEnv()
   local env = setmetatable({ }, { __index = _G })
   for k,v in pairs(sandboxEnv) do
@@ -115,62 +98,6 @@ local function runUrl(file, ...)
   error('Failed to download ' .. url)
 end
 
-local function createUserEnvironment(Util)
-  showStatus('Creating user environment')
-
-  if not fs.exists('usr/apps') then
-    fs.makeDir('usr/apps')
-  end
-  if not fs.exists('usr/autorun') then
-    fs.makeDir('usr/autorun')
-  end
-  if not fs.exists('usr/etc/fstab') then
-    Util.writeFile('usr/etc/fstab', 'usr gitfs kepler155c/opus-apps/' .. BRANCH)
-  end
-end
-
-local function createShellEnvironment(Util)
-  showStatus('Creating shell environment')
-
-  if not fs.exists('usr/config/shell') then
-    Util.writeTable('usr/config/shell', {
-      aliases  = shell.aliases(),
-      path     = 'usr/apps:sys/apps:' .. shell.path(),
-      lua_path = '/sys/apis:/usr/apis',
-    })
-  end
-
-  local config = Util.readTable('usr/config/shell')
-  if config.aliases then
-    for k in pairs(shell.aliases()) do
-      shell.clearAlias(k)
-    end
-    for k,v in pairs(config.aliases) do
-      shell.setAlias(k, v)
-    end
-  end
-  shell.setPath(config.path)
-  sandboxEnv.LUA_PATH = config.lua_path
-end
-
-local function loadExtensions()
-  local dir = 'sys/extensions'
-  local files = fs.list(dir)
-  table.sort(files)
-  for _,file in ipairs(files) do
-    showStatus('Loading ' .. file)
-    local s, m = kernel.run({
-      title = file:match('%d.(%S+).lua'),
-      hidden = true,
-      path = 'sys/apps/shell',
-      args = { fs.combine(dir, file) },
-      terminal = kernelWindow,
-    })
-    if not s then
-      error(m)
-    end
-  end
-end
 
 local args = { ... }
 
@@ -184,39 +111,32 @@ local s, m = pcall(function()
   else
     -- not local, run the file system directly from git
     _G.requireInjector = runUrl('sys/apis/injector.lua')
-    runUrl('sys/extensions/vfs.lua')
+    runUrl('sys/extensions/2.vfs.lua')
 
     -- install file system
     fs.mount('', 'gitfs', GIT_REPO)
   end
 
-  _G.requireInjector()
-  local Util = require('util')
+  showStatus('Starting kernel')
+  run('sys/apps/shell', 'sys/kernel.lua', args[1] and 6 or 7)
 
-  setLabel()
-  createUserEnvironment(Util)
-  createShellEnvironment(Util)
-
-  showStatus('Reticulating splines')
-  Util.run(makeEnv(), 'sys/kernel.lua')
-
-  loadExtensions()
-
-  showStatus('Mounting file systems')
-  fs.loadTab('usr/etc/fstab')
-
-  splashWindow.setVisible(false)
   if args[1] then
-    kernelWindow.setVisible(true)
-    kernelWindow.setVisible(false)
+    local s, m = kernel.run({
+      title = 'startup',
+      path = 'sys/apps/shell',
+      args = args,
+      haltOnExit = true,
+    })
+    if s then
+      kernel.raise(s.uid)
+    else
+      error(m)
+    end
   end
 
-  term.redirect(terminal)
-
-  _G.kernel.run({
-    path = 'sys/apps/shell',
-    args = args[1] and args or { 'sys/apps/multishell' },
-  })
+  splashWindow.setVisible(false)
+  kernelWindow.setVisible(true)
+  _G.kernel.start()
 end)
 
 if not s then
@@ -224,10 +144,7 @@ if not s then
   kernelWindow.setVisible(true)
   print('\nError loading Opus OS\n')
   _G.printError(m .. '\n')
-else
-  if _G.kernel.routines[1] then
-    _G.kernel.start()
-  end
+  term.redirect(terminal)
 end
 
 if fs.restore then
diff --git a/sys/extensions/3.network.lua b/sys/extensions/3.network.lua
index 0f25ffc..6451bf2 100644
--- a/sys/extensions/3.network.lua
+++ b/sys/extensions/3.network.lua
@@ -1,11 +1,21 @@
 local kernel = _G.kernel
 
+_G.network = { }
+
+local function startNetwork()
+	kernel.run({
+		title = 'Net daemon',
+		path = 'sys/apps/netdaemon.lua',
+		hidden = true,
+	})
+end
+
 kernel.hook('device_attach', function(_, eventData)
 	if eventData[1] == 'wireless_modem' then
-		kernel.run({
-			title = 'Net daemon',
-			path = 'sys/extensions/netdaemon.lua',
-			hidden = true,
-		})
+		startNetwork()
 	end
 end)
+
+if _G.device.wireless_modem then
+	startNetwork()
+end
diff --git a/sys/extensions/4.label.lua b/sys/extensions/4.label.lua
new file mode 100644
index 0000000..86a079c
--- /dev/null
+++ b/sys/extensions/4.label.lua
@@ -0,0 +1,15 @@
+-- Default label
+if not os.getComputerLabel() then
+  showStatus('Setting computer label')
+
+  local id = os.getComputerID()
+  if _G.turtle then
+    os.setComputerLabel('turtle_' .. id)
+  elseif _G.pocket then
+    os.setComputerLabel('pocket_' .. id)
+  elseif _G.commands then
+    os.setComputerLabel('command_' .. id)
+  else
+    os.setComputerLabel('computer_' .. id)
+  end
+end
diff --git a/sys/extensions/4.user.lua b/sys/extensions/4.user.lua
new file mode 100644
index 0000000..36c3a23
--- /dev/null
+++ b/sys/extensions/4.user.lua
@@ -0,0 +1,38 @@
+_G.requireInjector()
+
+local Util = require('util')
+
+local fs    = _G.fs
+local shell = _ENV.shell
+
+if not fs.exists('usr/apps') then
+  fs.makeDir('usr/apps')
+end
+if not fs.exists('usr/autorun') then
+  fs.makeDir('usr/autorun')
+end
+if not fs.exists('usr/etc/fstab') then
+  Util.writeFile('usr/etc/fstab', 'usr gitfs kepler155c/opus-apps/' .. _ENV.BRANCH)
+end
+
+if not fs.exists('usr/config/shell') then
+  Util.writeTable('usr/config/shell', {
+    aliases  = shell.aliases(),
+    path     = 'usr/apps:sys/apps:' .. shell.path(),
+    lua_path = 'sys/apis:usr/apis',
+  })
+end
+
+local config = Util.readTable('usr/config/shell')
+if config.aliases then
+  for k in pairs(shell.aliases()) do
+    shell.clearAlias(k)
+  end
+  for k,v in pairs(config.aliases) do
+    shell.setAlias(k, v)
+  end
+end
+shell.setPath(config.path)
+--sandboxEnv.LUA_PATH = config.lua_path
+
+fs.loadTab('usr/etc/fstab')
diff --git a/sys/apps/multishell b/sys/extensions/7.multishell.lua
similarity index 99%
rename from sys/apps/multishell
rename to sys/extensions/7.multishell.lua
index 04f2c33..80f73dc 100644
--- a/sys/apps/multishell
+++ b/sys/extensions/7.multishell.lua
@@ -14,7 +14,7 @@ local shell      = _ENV.shell
 local term       = _G.term
 local window     = _G.window
 
-local parentTerm = kernel.terminal.parent -- term.current()
+local parentTerm = _G.device.terminal -- term.current()
 local w,h = parentTerm.getSize()
 local overviewId
 local tabsDirty = false
@@ -378,6 +378,7 @@ end
 overviewId = multishell.openTab({
   path = 'sys/apps/Overview.lua',
   isOverview = true,
+  focusd = true,
 })
 kernel.find(overviewId).title = '+'
 
diff --git a/sys/kernel.lua b/sys/kernel.lua
index ac9a8a0..e50ff91 100644
--- a/sys/kernel.lua
+++ b/sys/kernel.lua
@@ -15,6 +15,7 @@ _G.kernel = {
   window = _G.term.current(),
 }
 
+local fs     = _G.fs
 local kernel = _G.kernel
 local os     = _G.os
 local term   = _G.term
@@ -86,6 +87,9 @@ function Routine:resume(event, ...)
       if #kernel.routines > 0 then
         os.queueEvent('kernel_focus', kernel.routines[1].uid)
       end
+      if self.haltOnExit then
+        kernel.halt()
+      end
     end
     return ok, result
   end
@@ -229,3 +233,22 @@ function kernel.start()
   end
   term.redirect(kernel.terminal)
 end
+
+local function loadExtensions(runLevel)
+  local dir = 'sys/extensions'
+  local files = fs.list(dir)
+  table.sort(files)
+  for _,file in ipairs(files) do
+    local level, name = file:match('(%d).(%S+).lua')
+--print(name)
+    if tonumber(level) <= runLevel then
+      local s, m = shell.run(fs.combine(dir, file))
+      if not s then
+        error(m)
+      end
+    end
+  end
+end
+
+local args = { ... }
+loadExtensions(args[1] and tonumber(args[1]) or 7)