diff --git a/.luacheckrc b/.luacheckrc
index b6f33a273..3de3dc84a 100644
--- a/.luacheckrc
+++ b/.luacheckrc
@@ -13,8 +13,6 @@ read_globals = {
     "KOBO_TOUCH_MIRRORED",
     "KOBO_SYNC_BRIGHTNESS_WITH_NICKEL",
     "DHINTCOUNT",
-    "DSCROLL_MODE",
-    "DGLOBALGAMMA",
     "DRENDER_MODE",
     "DGLOBAL_CACHE_SIZE_MINIMUM",
     "DGLOBAL_CACHE_FREE_PROPORTION",
diff --git a/defaults.lua b/defaults.lua
index a0f9e9893..3969f03db 100644
--- a/defaults.lua
+++ b/defaults.lua
@@ -15,10 +15,12 @@ DHINTCOUNT = 1
 --DFULL_SCREEN = 1
 
 -- scroll mode, 1 for true, 0 for false
-DSCROLL_MODE = 1
+-- no longer needed
+--DSCROLL_MODE = 1
 
 -- default gamma setting:
-DGLOBALGAMMA = 1.0
+-- no longer needed
+--DGLOBALGAMMA = 1.0
 
 -- DjVu page rendering mode (used in djvu.c:drawPage())
 -- See comments in djvureader.lua:DJVUReader:select_render_mode()
diff --git a/frontend/apps/reader/modules/readerview.lua b/frontend/apps/reader/modules/readerview.lua
index b538f8c6e..f02c8b99c 100644
--- a/frontend/apps/reader/modules/readerview.lua
+++ b/frontend/apps/reader/modules/readerview.lua
@@ -761,7 +761,7 @@ function ReaderView:onReadSettings(config)
         Screen:setScreenMode(screen_mode)
         self:onSetScreenMode(screen_mode, config:readSetting("rotation_mode"), true)
     end
-    self.state.gamma = config:readSetting("gamma") or DGLOBALGAMMA
+    self.state.gamma = config:readSetting("gamma") or 1.0
     local full_screen = config:readSetting("kopt_full_screen") or self.document.configurable.full_screen
     if full_screen == 0 then
         self.footer_visible = false
diff --git a/frontend/ui/data/koptoptions.lua b/frontend/ui/data/koptoptions.lua
index 915d024c5..4f9843562 100644
--- a/frontend/ui/data/koptoptions.lua
+++ b/frontend/ui/data/koptoptions.lua
@@ -49,7 +49,7 @@ local KoptOptions = {
                 name_text = S.VIEW_MODE,
                 toggle = {S.VIEW_SCROLL, S.VIEW_PAGE},
                 values = {1, 0},
-                default_value = DSCROLL_MODE,
+                default_value = 1,
                 event = "SetScrollMode",
                 args = {true, false},
                 name_text_hold_callback = optionsutil.showValues,
diff --git a/spec/unit/defaults_spec.lua b/spec/unit/defaults_spec.lua
index 650d08e05..e8efddc85 100644
--- a/spec/unit/defaults_spec.lua
+++ b/spec/unit/defaults_spec.lua
@@ -8,7 +8,7 @@ describe("defaults module", function()
 
     it("should load all defaults from defaults.lua", function()
         Defaults:init()
-        assert.is_same(105, #Defaults.defaults_name)
+        assert.is_same(103, #Defaults.defaults_name)
     end)
 
     it("should save changes to defaults.persistent.lua", function()
@@ -18,13 +18,13 @@ describe("defaults module", function()
         -- not in persistent but checked in defaults
         Defaults.changed[20] = true
         Defaults.changed[47] = true
-        Defaults.changed[54] = true
-        Defaults.changed[84] = true
-        Defaults.changed[100] = true
+        Defaults.changed[53] = true
+        Defaults.changed[82] = true
+        Defaults.changed[98] = true  --SEARCH_LIBRARY_PATH = ""
         Defaults:saveSettings()
-        assert.is_same(105, #Defaults.defaults_name)
-        assert.is_same("SEARCH_LIBRARY_PATH", Defaults.defaults_name[100])
-        assert.is_same("DTAP_ZONE_BACKWARD", Defaults.defaults_name[84])
+        assert.is_same(103, #Defaults.defaults_name)
+        assert.is_same("SEARCH_LIBRARY_PATH", Defaults.defaults_name[98])
+        assert.is_same("DTAP_ZONE_BACKWARD", Defaults.defaults_name[82])
         assert.is_same("DCREREADER_CONFIG_WORD_SPACING_LARGE", Defaults.defaults_name[47])
         assert.is_same("DCREREADER_CONFIG_H_MARGIN_SIZES_XXX_LARGE", Defaults.defaults_name[20])
         local fd = io.open(persistent_filename, "r")
@@ -45,17 +45,27 @@ DCREREADER_CONFIG_H_MARGIN_SIZES_XXX_LARGE = {
     [1] = 50,
     [2] = 50
 }
-DGLOBALGAMMA = 1
+DDOUBLE_TAP_ZONE_PREV_CHAPTER = {
+    ["y"] = 0,
+    ["x"] = 0,
+    ["h"] = 0.25,
+    ["w"] = 0.25
+}
 ]],
                        fd:read("*a"))
         fd:close()
 
         -- in persistent
         Defaults:init()
-        Defaults.changed[54] = true
-        Defaults.defaults_value[54] = 2
-        Defaults.changed[84] = true
-        Defaults.defaults_value[84] = {
+        Defaults.changed[53] = true
+        Defaults.defaults_value[53] = {
+            y = 0,
+            x = 0,
+            h = 0.25,
+            w = 0.75
+        }
+        Defaults.changed[82] = true
+        Defaults.defaults_value[82] = {
             y = 10,
             x = 10.125,
             h = 20.25,
@@ -80,7 +90,12 @@ DCREREADER_CONFIG_H_MARGIN_SIZES_XXX_LARGE = {
     [2] = 50,
     [1] = 50
 }
-DGLOBALGAMMA = 2
+DDOUBLE_TAP_ZONE_PREV_CHAPTER = {
+    ["y"] = 0,
+    ["x"] = 0,
+    ["h"] = 0.25,
+    ["w"] = 0.75
+}
 ]],
                        fd:read("*a"))
         fd:close()
@@ -116,7 +131,7 @@ DCREREADER_CONFIG_H_MARGIN_SIZES_LARGE = {
     [1] = 15
 }
 DHINTCOUNT = 2
-DGLOBALGAMMA = 1
+DGLOBAL_CACHE_FREE_PROPORTION = 1
 DCREREADER_VIEW_MODE = "page"
 ]],
                        fd:read("*a"))