diff --git a/java/com/google/gerrit/extensions/client/NullableBooleanPreferencesFieldComparator.java b/java/com/google/gerrit/extensions/client/NullableBooleanPreferencesFieldComparator.java
index 710e758..ccccceb 100644
--- a/java/com/google/gerrit/extensions/client/NullableBooleanPreferencesFieldComparator.java
+++ b/java/com/google/gerrit/extensions/client/NullableBooleanPreferencesFieldComparator.java
@@ -37,7 +37,7 @@
    *   <tr><td> true </td> <td> true </td> <td> true </td></tr>
    *   <tr><td> true </td> <td> false </td> <td> true </td></tr>
    *   <tr><td> true </td> <td> null </td> <td> true </td></tr>
-   *   <tr><td> false </td> <td> true </td> <td> true </td></tr>
+   *   <tr><td> false </td> <td> true </td> <td> false </td></tr>
    *   <tr><td> false </td> <td> false </td> <td> null </td></tr>
    *   <tr><td> false </td> <td> null </td> <td> null </td></tr>
    *   <tr><td> null </td> <td> true </td> <td> true </td></tr>
@@ -49,7 +49,7 @@
    * practically referring to {@code null} values as {@code false} anyway. Preferences equality
    * methods should reflect this state.
    */
-  static boolean equalBooleanPreferencesFields(@Nullable Boolean a, @Nullable Boolean b) {
+  public static boolean equalBooleanPreferencesFields(@Nullable Boolean a, @Nullable Boolean b) {
     return Objects.equals(
         Objects.requireNonNullElse(a, false), Objects.requireNonNullElse(b, false));
   }
diff --git a/java/com/google/gerrit/server/config/ConfigUtil.java b/java/com/google/gerrit/server/config/ConfigUtil.java
index e76207c..121c62e 100644
--- a/java/com/google/gerrit/server/config/ConfigUtil.java
+++ b/java/com/google/gerrit/server/config/ConfigUtil.java
@@ -371,8 +371,12 @@
         } else if (isLong(t)) {
           f.set(s, cfg.getLong(section, sub, n, (Long) d));
         } else if (isBoolean(t)) {
+          // Sets the field if:
+          // - 'cfg' value is 'true'.
+          // - the default value is 'true'.
+          // - i is set.
           boolean b = cfg.getBoolean(section, sub, n, (Boolean) d);
-          if (b || i != null) {
+          if (b || (Boolean) d || i != null) {
             f.set(s, b);
           }
         } else if (t.isEnum()) {
@@ -427,10 +431,13 @@
             requireNonNull(val, "Default cannot be null for: " + n);
           }
         }
-        if (!isBoolean(t) || (boolean) val) {
+        if (!isBoolean(t) || (boolean) val || (Boolean) f.get(defaults)) {
           // To reproduce the same behavior as in the loadSection method above, values are
           // explicitly set for all types, except the boolean type. For the boolean type, the value
-          // is set only if it is 'true' (so, the false value is omitted in the result object).
+          // is set only in the following cases:
+          // - 'cfg' value is 'true'.
+          // - the default value is 'true'.
+          // Otherwise, false values are omitted in the result object.
           f.set(s, val);
         }
       }
diff --git a/javatests/com/google/gerrit/acceptance/api/accounts/DiffPreferencesIT.java b/javatests/com/google/gerrit/acceptance/api/accounts/DiffPreferencesIT.java
index e3380c0..4f27075 100644
--- a/javatests/com/google/gerrit/acceptance/api/accounts/DiffPreferencesIT.java
+++ b/javatests/com/google/gerrit/acceptance/api/accounts/DiffPreferencesIT.java
@@ -64,6 +64,9 @@
 
     DiffPreferencesInfo o = gApi.accounts().id(admin.id().get()).setDiffPreferences(i);
     assertPrefs(o, i);
+    // Re-getting the preferences should yield the same fields
+    o = gApi.accounts().id(admin.id().get()).getDiffPreferences();
+    assertPrefs(o, i);
 
     // Partially fill input record
     i = new DiffPreferencesInfo();
@@ -74,6 +77,38 @@
   }
 
   @Test
+  public void setDiffPreferences_booleanHandling() throws Exception {
+    DiffPreferencesInfo update = new DiffPreferencesInfo();
+    update.showLineEndings = true; // Default is 'true'
+    update.lineWrapping = true; // Default is 'false'
+    update.showTabs = false; // Default is 'true'
+    update.hideTopMenu = false; // Default is 'false'
+    update.intralineDifference = null; // Default is 'true'
+    update.retainHeader = null; // Default is 'false'
+
+    DiffPreferencesInfo o = gApi.accounts().id(admin.id().get()).setDiffPreferences(update);
+
+    // Explicitly assert configured values
+    assertThat(o.showLineEndings).isTrue();
+    assertThat(o.lineWrapping).isTrue();
+    assertThat(o.showTabs).isFalse();
+    assertThat(o.hideTopMenu).isNull(); // Both new value and default are false, omitted
+    assertThat(o.intralineDifference).isTrue();
+    assertThat(o.retainHeader).isNull(); // new value is 'null' and default is false, omitted
+
+    // assert unaffected fields
+    assertPrefs(
+        o,
+        DiffPreferencesInfo.defaults(),
+        "showLineEndings",
+        "lineWrapping",
+        "showTabs",
+        "hideTopMenu",
+        "intralineDifference",
+        "retainHeader");
+  }
+
+  @Test
   public void getDiffPreferencesWithConfiguredDefaults() throws Exception {
     DiffPreferencesInfo d = DiffPreferencesInfo.defaults();
     int newLineLength = d.lineLength + 10;
diff --git a/javatests/com/google/gerrit/server/config/ConfigUtilTest.java b/javatests/com/google/gerrit/server/config/ConfigUtilTest.java
index 035878c..f8c04a9 100644
--- a/javatests/com/google/gerrit/server/config/ConfigUtilTest.java
+++ b/javatests/com/google/gerrit/server/config/ConfigUtilTest.java
@@ -107,7 +107,7 @@
     assertThat(out.ld).isEqualTo(d.ld);
     assertThat(out.b).isEqualTo(in.b);
     assertThat(out.bb).isEqualTo(in.bb);
-    assertThat(out.bd).isNull();
+    assertThat(out.bd).isFalse();
     assertThat(out.s).isEqualTo(in.s);
     assertThat(out.sd).isEqualTo(d.sd);
     assertThat(out.nd).isNull();