diff --git a/frontend/ui/uimanager.lua b/frontend/ui/uimanager.lua
index e5c85b640..60c625e42 100644
--- a/frontend/ui/uimanager.lua
+++ b/frontend/ui/uimanager.lua
@@ -29,7 +29,6 @@ local UIManager = {
 
     event_handlers = nil,
 
-    _running = true,
     _now = time.now(),
     _window_stack = {},
     _task_queue = {},
@@ -68,7 +67,11 @@ function UIManager:init()
         self:nextTick(function()
             Device:saveSettings()
             Device:powerOff()
-            self:quit(Device:isKobo() and 88)
+            if Device:isKobo() then
+                self:quit(88)
+            else
+                self:quit()
+            end
         end)
     end
     self.reboot_action = function()
@@ -81,11 +84,19 @@ function UIManager:init()
         self:nextTick(function()
             Device:saveSettings()
             Device:reboot()
-            self:quit(Device:isKobo() and 88)
+            if Device:isKobo() then
+                self:quit(88)
+            else
+                self:quit()
+            end
         end)
     end
 
     Device:_setEventHandlers(self)
+
+    -- A simple wrapper for UIManager:quit()
+    -- This may be overwritten by setRunForeverMode(); for testing purposes
+    self._gated_quit = self.quit
 end
 
 --[[--
@@ -116,7 +127,6 @@ function UIManager:show(widget, refreshtype, refreshregion, x, y, refreshdither)
     end
     logger.dbg("show widget:", widget.id or widget.name or tostring(widget))
 
-    self._running = true
     local window = {x = x or 0, y = y or 0, widget = widget}
     -- put this window on top of the topmost non-modal window
     for i = #self._window_stack, 0, -1 do
@@ -728,13 +738,16 @@ function UIManager:isWidgetShown(widget)
 end
 
 --- Signals to quit.
+-- An exit_code of false is not allowed.
 function UIManager:quit(exit_code)
-    if not self._running then return end
-    logger.info("quitting uimanager with exit code:", exit_code or 0)
-    self._exit_code = exit_code
+    if exit_code == false then
+        logger.err("UIManager:quit() called with false")
+        return
+    end
+    -- Also honor older exit codes; default to 0
+    self._exit_code = exit_code or self._exit_code or 0
+    logger.info("quitting uimanager with exit code:", self._exit_code)
     self._task_queue_dirty = false
-    self._running = false
-    self._run_forever = nil
     for i = #self._window_stack, 1, -1 do
         table.remove(self._window_stack, i)
     end
@@ -749,6 +762,21 @@ function UIManager:quit(exit_code)
         self.looper:close()
         self.looper = nil
     end
+    return self._exit_code
+end
+dbg:guard(UIManager, 'quit',
+    function(self, exit_code)
+        assert(exit_code ~= false, "exit_code == false is not supported")
+    end)
+
+-- Disable automatic UIManager quit; for testing purposes
+function UIManager:setRunForeverMode()
+    self._gated_quit = function() return false end
+end
+
+-- Enable automatic UIManager quit; for testing purposes
+function UIManager:unsetRunForeverMode()
+    self._gated_quit = self.quit
 end
 
 --[[--
@@ -1345,10 +1373,11 @@ function UIManager:handleInput()
         --]]
 
         -- stop when we have no window to show
-        if not self._window_stack[1] and not self._run_forever then
+        if not self._window_stack[1] then
             logger.info("no dialog left to show")
-            self:quit()
-            return nil
+            if self:_gated_quit() ~= false then
+                return nil
+            end
         end
 
         self:_repaint()
@@ -1446,8 +1475,6 @@ This is the main loop of the UI controller.
 It is intended to manage input events and delegate them to dialogs.
 --]]
 function UIManager:run()
-    self._running = true
-
     -- Tell PowerD that we're ready
     Device:getPowerDevice():readyUI()
 
@@ -1455,9 +1482,9 @@ function UIManager:run()
     -- currently there is no Turbo support for Windows
     -- use our own main loop
     if not self.looper then
-        while self._running do
+        repeat
             self:handleInput()
-        end
+        until self._exit_code
     else
         self.looper:add_callback(function() self:handleInput() end)
         self.looper:start()
@@ -1466,12 +1493,6 @@ function UIManager:run()
     return self._exit_code
 end
 
--- run uimanager forever for testing purpose
-function UIManager:runForever()
-    self._run_forever = true
-    return self:run()
-end
-
 --[[--
 Executes all the operations of a suspension (i.e., sleep) request.
 
diff --git a/spec/unit/autofrontlight_spec.lua b/spec/unit/autofrontlight_spec.lua
index 416f641fb..3ee300832 100644
--- a/spec/unit/autofrontlight_spec.lua
+++ b/spec/unit/autofrontlight_spec.lua
@@ -45,7 +45,7 @@ describe("AutoFrontlight widget tests", function()
             close()
 
         UIManager = require("ui/uimanager")
-        UIManager._run_forever = true
+        UIManager:setRunForeverMode()
 
         requireBackgroundRunner()
         class = dofile("plugins/autofrontlight.koplugin/main.lua")
diff --git a/spec/unit/autosuspend_spec.lua b/spec/unit/autosuspend_spec.lua
index a0492d3cc..79745306c 100644
--- a/spec/unit/autosuspend_spec.lua
+++ b/spec/unit/autosuspend_spec.lua
@@ -13,7 +13,7 @@ describe("AutoSuspend", function()
             Device.input.waitEvent = function() end
             local UIManager = require("ui/uimanager")
             stub(UIManager, "suspend")
-            UIManager._run_forever = true
+            UIManager:setRunForeverMode()
             G_reader_settings:saveSetting("auto_suspend_timeout_seconds", 10)
             require("mock_time"):install()
             -- Reset UIManager:getTime()
@@ -71,7 +71,7 @@ describe("AutoSuspend", function()
             Device.input.waitEvent = function() end
             local UIManager = require("ui/uimanager")
             stub(UIManager, "poweroff_action")
-            UIManager._run_forever = true
+            UIManager:setRunForeverMode()
             G_reader_settings:saveSetting("autoshutdown_timeout_seconds", 10)
             require("mock_time"):install()
             -- Reset UIManager:getTime()
diff --git a/spec/unit/background_runner_spec.lua b/spec/unit/background_runner_spec.lua
index 550fd1886..1210be294 100644
--- a/spec/unit/background_runner_spec.lua
+++ b/spec/unit/background_runner_spec.lua
@@ -12,7 +12,7 @@ describe("BackgroundRunner widget tests", function()
         MockTime = require("mock_time")
         MockTime:install()
         UIManager = require("ui/uimanager")
-        UIManager._run_forever = true
+        UIManager:setRunForeverMode()
         requireBackgroundRunner()
     end)
 
diff --git a/spec/unit/background_task_plugin_spec.lua b/spec/unit/background_task_plugin_spec.lua
index 71bb2c6d0..3c72c8f6c 100644
--- a/spec/unit/background_task_plugin_spec.lua
+++ b/spec/unit/background_task_plugin_spec.lua
@@ -9,7 +9,7 @@ describe("BackgroundTaskPlugin", function()
         MockTime:install()
         local Device = require("device")
         Device.input.waitEvent = function() end
-        UIManager._run_forever = true
+        UIManager:setRunForeverMode()
         requireBackgroundRunner()
         -- Monkey patch this method to notify BackgroundRunner
         -- as it is not accessible to UIManager in these tests
diff --git a/spec/unit/httpclient_spec.lua b/spec/unit/httpclient_spec.lua
index a9df16fc7..506d35cc9 100644
--- a/spec/unit/httpclient_spec.lua
+++ b/spec/unit/httpclient_spec.lua
@@ -35,6 +35,7 @@ describe("HTTP client module #notest #nocov", function()
                 url = url,
             }, response_callback)
         end
-        UIManager:runForever()
+        UIManager:setRunForeverMode()
+        UIManager:run()
     end)
 end)
diff --git a/spec/unit/readerlink_spec.lua b/spec/unit/readerlink_spec.lua
index e94e0fca8..7ee42ab80 100644
--- a/spec/unit/readerlink_spec.lua
+++ b/spec/unit/readerlink_spec.lua
@@ -28,6 +28,7 @@ describe("ReaderLink module", function()
 
     it("should jump to links in pdf page mode", function()
         UIManager:quit()
+        UIManager._exit_code = nil
         local readerui = ReaderUI:new{
             dimen = Screen:getSize(),
             document = DocumentRegistry:openDocument(sample_pdf),
@@ -44,6 +45,7 @@ describe("ReaderLink module", function()
 
     it("should jump to links in pdf scroll mode", function()
         UIManager:quit()
+        UIManager._exit_code = nil
         local readerui = ReaderUI:new{
             dimen = Screen:getSize(),
             document = DocumentRegistry:openDocument(sample_pdf),
@@ -78,6 +80,7 @@ describe("ReaderLink module", function()
 
     it("should be able to go back after link jump in pdf page mode", function()
         UIManager:quit()
+        UIManager._exit_code = nil
         local readerui = ReaderUI:new{
             dimen = Screen:getSize(),
             document = DocumentRegistry:openDocument(sample_pdf),
@@ -96,6 +99,7 @@ describe("ReaderLink module", function()
 
     it("should be able to go back after link jump in pdf scroll mode", function()
         UIManager:quit()
+        UIManager._exit_code = nil
         local readerui = ReaderUI:new{
             dimen = Screen:getSize(),
             document = DocumentRegistry:openDocument(sample_pdf),
@@ -116,6 +120,7 @@ describe("ReaderLink module", function()
 
     it("should be able to go back to the same position after link jump in pdf scroll mode", function()
         UIManager:quit()
+        UIManager._exit_code = nil
         local expected_page_states = {
             {
                 gamma = 1,
diff --git a/spec/unit/spore_spec.lua b/spec/unit/spore_spec.lua
index f1d4c2990..a8cf17592 100644
--- a/spec/unit/spore_spec.lua
+++ b/spec/unit/spore_spec.lua
@@ -102,7 +102,8 @@ describe("Lua Spore modules with async http request #notest #nocov", function()
         client:enable("Format.JSON")
         client:enable("AsyncHTTP", {thread = co})
         coroutine.resume(co)
-        UIManager:runForever()
+        UIManager:setRunForeverMode()
+        UIManager:run()
     end)
 
     it("should complete POST request", function()
@@ -117,6 +118,7 @@ describe("Lua Spore modules with async http request #notest #nocov", function()
         client:enable("Format.JSON")
         client:enable("AsyncHTTP", {thread = co})
         coroutine.resume(co)
-        UIManager:runForever()
+        UIManager:setRunForeverMode()
+        UIManager:run()
     end)
 end)