diff --git a/base b/base
index 5a83d4aad..f342e7fed 160000
--- a/base
+++ b/base
@@ -1 +1 @@
-Subproject commit 5a83d4aaded90420306380613ccdc4613a53a9ce
+Subproject commit f342e7fedabe46dde7a54f30e25d555d4d311879
diff --git a/frontend/apps/reader/modules/readerscreenshot.lua b/frontend/apps/reader/modules/readerscreenshot.lua
index 0698c468f..8fad7d925 100644
--- a/frontend/apps/reader/modules/readerscreenshot.lua
+++ b/frontend/apps/reader/modules/readerscreenshot.lua
@@ -7,7 +7,9 @@ local InfoMessage = require("ui/widget/infomessage")
 local _ = require("gettext")
 local DEBUG = require("dbg")
 
-local ReaderScreenshot = InputContainer:new{}
+local ReaderScreenshot = InputContainer:new{
+    datetime_name = "screenshots/Screenshot_%Y-%b-%d_%Hh%M.png",
+}
 
 function ReaderScreenshot:init()
     local diagonal = math.sqrt(
@@ -32,16 +34,13 @@ function ReaderScreenshot:init()
     }
 end
 
-function ReaderScreenshot:onScreenshot()
-    if os.execute("screenshot") ~= 0 then
-        local screenshot_name = os.date("screenshots/Screenshot_%Y-%B-%d_%Hh%M.pam")
-        UIManager:show(InfoMessage:new{
-            text = _("Writing screen to ")..screenshot_name,
-            timeout = 2,
-        })
-        Screen.bb:writePAM(screenshot_name)
-        DEBUG(screenshot_name)
-    end
+function ReaderScreenshot:onScreenshot(filename)
+    local screenshot_name = filename or os.date(self.datetime_name)
+    UIManager:show(InfoMessage:new{
+        text = _("Writing screen to ")..screenshot_name,
+        timeout = 2,
+    })
+    Screen:shot(screenshot_name)
     UIManager.full_refresh = true
     return true
 end
diff --git a/frontend/device/screen.lua b/frontend/device/screen.lua
index 81ef62f9d..d755bb3cc 100644
--- a/frontend/device/screen.lua
+++ b/frontend/device/screen.lua
@@ -174,10 +174,14 @@ function Screen:restoreFromSavedBB()
     end
 end
 
+function Screen:shot(filename)
+    DEBUG("write PNG file", filename)
+    self.bb:writePNG(filename)
+end
+
 function Screen:close()
     DEBUG("close screen framebuffer")
     self.fb:close()
 end
 
-
 return Screen
diff --git a/plugins/zsync.koplugin/main.lua b/plugins/zsync.koplugin/main.lua
index 61f0f6eff..ae724abe5 100644
--- a/plugins/zsync.koplugin/main.lua
+++ b/plugins/zsync.koplugin/main.lua
@@ -1,8 +1,5 @@
-local FileManagerHistory = require("apps/filemanager/filemanagerhistory")
-local FileManagerMenu = require("apps/filemanager/filemanagermenu")
 local InputContainer = require("ui/widget/container/inputcontainer")
 local FrameContainer = require("ui/widget/container/framecontainer")
-local FileManager = require("apps/filemanager/filemanager")
 local VerticalGroup = require("ui/widget/verticalgroup")
 local VerticalSpan = require("ui/widget/verticalspan")
 local ButtonDialog = require("ui/widget/buttondialog")
diff --git a/spec/unit/filemanager_spec.lua b/spec/unit/filemanager_spec.lua
new file mode 100644
index 000000000..9eded5650
--- /dev/null
+++ b/spec/unit/filemanager_spec.lua
@@ -0,0 +1,18 @@
+require("commonrequire")
+local FileManager = require("apps/filemanager/filemanager")
+local UIManager = require("ui/uimanager")
+local Screen = require("device").screen
+local DEBUG = require("dbg")
+
+describe("FileManager module", function()
+    it("should show file manager", function()
+        UIManager:quit()
+        local filemanager = FileManager:new{
+            dimen = Screen:getSize(),
+            root_path = "../../test",
+        }
+        UIManager:show(filemanager)
+        UIManager:scheduleIn(1, function() UIManager:close(filemanager) end)
+        UIManager:run()
+    end)
+end)
diff --git a/spec/unit/readerscreenshot_spec.lua b/spec/unit/readerscreenshot_spec.lua
new file mode 100644
index 000000000..245b43559
--- /dev/null
+++ b/spec/unit/readerscreenshot_spec.lua
@@ -0,0 +1,38 @@
+require("commonrequire")
+local DocumentRegistry = require("document/documentregistry")
+local ReaderUI = require("apps/reader/readerui")
+local lfs = require("libs/libkoreader-lfs")
+local UIManager = require("ui/uimanager")
+local Screen = require("device").screen
+local Event = require("ui/event")
+local DEBUG = require("dbg")
+
+describe("ReaderScreenshot module", function()
+    local sample_epub = "spec/front/unit/data/leaves.epub"
+    local readerui
+    setup(function()
+        readerui = ReaderUI:new{
+            document = DocumentRegistry:openDocument(sample_epub),
+        }
+    end)
+    it("should get screenshot in portrait", function()
+        local name = "screenshots/reader_screenshot_portrait.png"
+        readerui:handleEvent(Event:new("ChangeScreenMode", "portrait"))
+        UIManager:quit()
+        UIManager:show(readerui)
+        UIManager:scheduleIn(1, function() UIManager:close(readerui) end)
+        UIManager:run()
+        readerui.screenshot:onScreenshot(name)
+        assert.truthy(lfs.attributes(name, "mode"))
+    end)
+    it("should get screenshot in landscape", function()
+        local name = "screenshots/reader_screenshot_landscape.png"
+        readerui:handleEvent(Event:new("ChangeScreenMode", "landscape"))
+        UIManager:quit()
+        UIManager:show(readerui)
+        UIManager:scheduleIn(2, function() UIManager:close(readerui) end)
+        UIManager:run()
+        readerui.screenshot:onScreenshot(name)
+        assert.truthy(lfs.attributes(name, "mode"))
+    end)
+end)
diff --git a/spec/unit/readerui_spec.lua b/spec/unit/readerui_spec.lua
index 241797d20..9b349c7ed 100644
--- a/spec/unit/readerui_spec.lua
+++ b/spec/unit/readerui_spec.lua
@@ -2,13 +2,17 @@ require("commonrequire")
 local DocumentRegistry = require("document/documentregistry")
 local ReaderUI = require("apps/reader/readerui")
 local DocSettings = require("docsettings")
+local UIManager = require("ui/uimanager")
 local DEBUG = require("dbg")
 
 describe("Readerui module", function()
     local sample_epub = "spec/front/unit/data/leaves.epub"
-    local readerui = ReaderUI:new{
-        document = DocumentRegistry:openDocument(sample_epub),
-    }
+    local readerui
+    setup(function()
+        readerui = ReaderUI:new{
+            document = DocumentRegistry:openDocument(sample_epub),
+        }
+    end)
     it("should save settings", function()
         -- remove history settings and sidecar settings
         DocSettings:open(sample_epub):clear()
@@ -21,6 +25,12 @@ describe("Readerui module", function()
         assert.are.same(doc_settings.data.last_xpointer,
                 readerui.doc_settings.data.last_xpointer)
     end)
+    it("should show reader", function()
+        UIManager:quit()
+        UIManager:show(readerui)
+        UIManager:scheduleIn(1, function() UIManager:close(readerui) end)
+        UIManager:run()
+    end)
     it("should close document", function()
         readerui:closeDocument()
         assert(readerui.document == nil)