diff --git a/flutter/lib/mobile/pages/remote_page.dart b/flutter/lib/mobile/pages/remote_page.dart
index a8446de20225..70ebb987797b 100644
--- a/flutter/lib/mobile/pages/remote_page.dart
+++ b/flutter/lib/mobile/pages/remote_page.dart
@@ -224,7 +224,9 @@ class _RemotePageState extends State<RemotePage> {
 
   void _handleNonIOSSoftKeyboardInput(String newValue) {
     _lastComposingChangeValid = _textController.value.isComposingRangeValid;
-    if (_lastComposingChangeValid) {
+    if (_lastComposingChangeValid && newValue.length > _value.length) {
+      // Only early return if is composing new words.
+      // We need to send `backspace` immediately if is deleting letters.
       return;
     }
     var oldValue = _value;
diff --git a/flutter/lib/models/input_model.dart b/flutter/lib/models/input_model.dart
index 1b2a9736ee2a..3f413c499bf9 100644
--- a/flutter/lib/models/input_model.dart
+++ b/flutter/lib/models/input_model.dart
@@ -544,26 +544,40 @@ class InputModel {
       handleKeyDownEventModifiers(e);
     }
 
-    // The physicalKey.usbHidUsage may be not correct for soft keyboard on Android.
-    // iOS does not have this issue.
-    // 1. Open the soft keyboard on Android
-    // 2. Switch to input method like zh/ko/ja
-    // 3. Click Backspace and Enter on the soft keyboard or physical keyboard
-    // 4. The physicalKey.usbHidUsage is not correct.
-    // PhysicalKeyboardKey#8ac83(usbHidUsage: "0x1100000042", debugName: "Key with ID 0x1100000042")
-    // LogicalKeyboardKey#2604c(keyId: "0x10000000d", keyLabel: "Enter", debugName: "Enter")
-    //
-    // The correct PhysicalKeyboardKey should be
-    // PhysicalKeyboardKey#e14a9(usbHidUsage: "0x00070028", debugName: "Enter")
-    // https://github.com/flutter/flutter/issues/157771
-    // We cannot use the debugName to determine the key is correct or not, because it's null in release mode.
-    // to-do: `isLegacyModeKeys` is not the best workaround, we need to find a better way to fix this issue.
-    final isLegacyModeKeys = ['Backspace', 'Enter'].contains(e.logicalKey.keyLabel);
-    final isMobileAndPeerNotAndroid =
-        isMobile && peerPlatform != kPeerPlatformAndroid;
+    bool isMobileAndMapMode = false;
+    if (isMobile) {
+      // Do not use map mode if mobile -> Android. Android does not support map mode for now.
+      // Because simulating the physical key events(uhid) which requires root permission is not supported.
+      if (peerPlatform != kPeerPlatformAndroid) {
+        if (isIOS) {
+          isMobileAndMapMode = true;
+        } else {
+          // The physicalKey.usbHidUsage may be not correct for soft keyboard on Android.
+          // iOS does not have this issue.
+          // 1. Open the soft keyboard on Android
+          // 2. Switch to input method like zh/ko/ja
+          // 3. Click Backspace and Enter on the soft keyboard or physical keyboard
+          // 4. The physicalKey.usbHidUsage is not correct.
+          // PhysicalKeyboardKey#8ac83(usbHidUsage: "0x1100000042", debugName: "Key with ID 0x1100000042")
+          // LogicalKeyboardKey#2604c(keyId: "0x10000000d", keyLabel: "Enter", debugName: "Enter")
+          //
+          // The correct PhysicalKeyboardKey should be
+          // PhysicalKeyboardKey#e14a9(usbHidUsage: "0x00070028", debugName: "Enter")
+          // https://github.com/flutter/flutter/issues/157771
+          // We cannot use the debugName to determine the key is correct or not, because it's null in release mode.
+          // The normal `usbHidUsage` for keyboard shoud be between [0x00000010, 0x000c029f]
+          // https://github.com/flutter/flutter/blob/c051b69e2a2224300e20d93dbd15f4b91e8844d1/packages/flutter/lib/src/services/keyboard_key.g.dart#L5332 - 5600
+          final isNormalHsbHidUsage = (e.physicalKey.usbHidUsage >> 20) == 0;
+          isMobileAndMapMode = isNormalHsbHidUsage &&
+              // No need to check `!['Backspace', 'Enter'].contains(e.logicalKey.keyLabel)`
+              // But we still add it for more reliability.
+              !['Backspace', 'Enter'].contains(e.logicalKey.keyLabel);
+        }
+      }
+    }
     final isDesktopAndMapMode =
-        isDesktop || isWebDesktop && keyboardMode == kKeyMapMode;
-    if (!isLegacyModeKeys && (isMobileAndPeerNotAndroid || isDesktopAndMapMode)) {
+        isDesktop || (isWebDesktop && keyboardMode == kKeyMapMode);
+    if (isMobileAndMapMode || isDesktopAndMapMode) {
       // FIXME: e.character is wrong for dead keys, eg: ^ in de
       newKeyboardMode(
           e.character ?? '',