diff --git a/ArchiSteamFarm/Bot.cs b/ArchiSteamFarm/Bot.cs
index 8ba7ab93f..c5e3f5e17 100755
--- a/ArchiSteamFarm/Bot.cs
+++ b/ArchiSteamFarm/Bot.cs
@@ -1450,7 +1450,45 @@ namespace ArchiSteamFarm {
 			ArchiLogger.LogGenericInfo(Strings.BotAuthenticatorConverting);
 
 			try {
-				MobileAuthenticator authenticator = JsonConvert.DeserializeObject<MobileAuthenticator>(await RuntimeCompatibility.File.ReadAllTextAsync(maFilePath).ConfigureAwait(false));
+				string json = await RuntimeCompatibility.File.ReadAllTextAsync(maFilePath).ConfigureAwait(false);
+
+				if (string.IsNullOrEmpty(json)) {
+					ArchiLogger.LogGenericError(string.Format(Strings.ErrorIsEmpty, nameof(json)));
+
+					return;
+				}
+
+				MobileAuthenticator authenticator = JsonConvert.DeserializeObject<MobileAuthenticator>(json);
+
+				if (authenticator == null) {
+					ArchiLogger.LogNullError(nameof(authenticator));
+
+					return;
+				}
+
+				if (!authenticator.HasValidDeviceID) {
+					ArchiLogger.LogGenericWarning(Strings.BotAuthenticatorInvalidDeviceID);
+
+					if (string.IsNullOrEmpty(DeviceID)) {
+						string deviceID = Program.GetUserInput(ASF.EUserInputType.DeviceID, BotName);
+
+						if (string.IsNullOrEmpty(deviceID)) {
+							return;
+						}
+
+						SetUserInput(ASF.EUserInputType.DeviceID, deviceID);
+					}
+
+					if (!MobileAuthenticator.IsValidDeviceID(DeviceID)) {
+						ArchiLogger.LogGenericWarning(Strings.BotAuthenticatorInvalidDeviceID);
+
+						return;
+					}
+
+					authenticator.CorrectDeviceID(DeviceID);
+				}
+
+				authenticator.Init(this);
 				await BotDatabase.SetMobileAuthenticator(authenticator).ConfigureAwait(false);
 				File.Delete(maFilePath);
 			} catch (Exception e) {
@@ -1459,32 +1497,6 @@ namespace ArchiSteamFarm {
 				return;
 			}
 
-			if (BotDatabase.MobileAuthenticator == null) {
-				ArchiLogger.LogNullError(nameof(BotDatabase.MobileAuthenticator));
-
-				return;
-			}
-
-			BotDatabase.MobileAuthenticator.Init(this);
-
-			if (!BotDatabase.MobileAuthenticator.HasCorrectDeviceID) {
-				ArchiLogger.LogGenericWarning(Strings.BotAuthenticatorInvalidDeviceID);
-
-				if (string.IsNullOrEmpty(DeviceID)) {
-					string deviceID = Program.GetUserInput(ASF.EUserInputType.DeviceID, BotName);
-
-					if (string.IsNullOrEmpty(deviceID)) {
-						await BotDatabase.SetMobileAuthenticator().ConfigureAwait(false);
-
-						return;
-					}
-
-					SetUserInput(ASF.EUserInputType.DeviceID, deviceID);
-				}
-
-				await BotDatabase.CorrectMobileAuthenticatorDeviceID(DeviceID).ConfigureAwait(false);
-			}
-
 			ArchiLogger.LogGenericInfo(Strings.BotAuthenticatorImportFinished);
 		}
 
diff --git a/ArchiSteamFarm/BotDatabase.cs b/ArchiSteamFarm/BotDatabase.cs
index 7b6ba4987..b43452ad9 100644
--- a/ArchiSteamFarm/BotDatabase.cs
+++ b/ArchiSteamFarm/BotDatabase.cs
@@ -137,18 +137,6 @@ namespace ArchiSteamFarm {
 			}
 		}
 
-		internal async Task CorrectMobileAuthenticatorDeviceID(string deviceID) {
-			if (string.IsNullOrEmpty(deviceID) || (MobileAuthenticator == null)) {
-				ASF.ArchiLogger.LogNullError(nameof(deviceID) + " || " + nameof(MobileAuthenticator));
-
-				return;
-			}
-
-			if (MobileAuthenticator.CorrectDeviceID(deviceID)) {
-				await Save().ConfigureAwait(false);
-			}
-		}
-
 		internal static async Task<BotDatabase> CreateOrLoad(string filePath) {
 			if (string.IsNullOrEmpty(filePath)) {
 				ASF.ArchiLogger.LogNullError(nameof(filePath));
diff --git a/ArchiSteamFarm/MobileAuthenticator.cs b/ArchiSteamFarm/MobileAuthenticator.cs
index 623b383eb..d27709c5f 100644
--- a/ArchiSteamFarm/MobileAuthenticator.cs
+++ b/ArchiSteamFarm/MobileAuthenticator.cs
@@ -45,8 +45,7 @@ namespace ArchiSteamFarm {
 		private static DateTime LastSteamTimeCheck;
 		private static int? SteamTimeDifference;
 
-		// "ERROR" is being used by SteamDesktopAuthenticator
-		internal bool HasCorrectDeviceID => !string.IsNullOrEmpty(DeviceID) && !DeviceID.Equals("ERROR");
+		internal bool HasValidDeviceID => !string.IsNullOrEmpty(DeviceID) && IsValidDeviceID(DeviceID);
 
 #pragma warning disable 649
 		[JsonProperty(PropertyName = "identity_secret", Required = Required.Always)]
@@ -65,20 +64,20 @@ namespace ArchiSteamFarm {
 
 		private MobileAuthenticator() { }
 
-		internal bool CorrectDeviceID(string deviceID) {
+		internal void CorrectDeviceID(string deviceID) {
 			if (string.IsNullOrEmpty(deviceID)) {
 				Bot.ArchiLogger.LogNullError(nameof(deviceID));
 
-				return false;
+				return;
 			}
 
-			if (!string.IsNullOrEmpty(DeviceID) && DeviceID.Equals(deviceID)) {
-				return false;
+			if (!IsValidDeviceID(deviceID)) {
+				Bot.ArchiLogger.LogGenericError(string.Format(Strings.ErrorIsInvalid, nameof(deviceID)));
+
+				return;
 			}
 
 			DeviceID = deviceID;
-
-			return true;
 		}
 
 		internal async Task<string> GenerateToken() {
@@ -100,7 +99,7 @@ namespace ArchiSteamFarm {
 				return null;
 			}
 
-			if (!HasCorrectDeviceID) {
+			if (!HasValidDeviceID) {
 				Bot.ArchiLogger.LogGenericError(Strings.ErrorMobileAuthenticatorInvalidDeviceID);
 
 				return null;
@@ -128,7 +127,7 @@ namespace ArchiSteamFarm {
 		}
 
 		internal async Task<HashSet<Confirmation>> GetConfirmations(Steam.ConfirmationDetails.EType acceptedType = Steam.ConfirmationDetails.EType.Unknown) {
-			if (!HasCorrectDeviceID) {
+			if (!HasValidDeviceID) {
 				Bot.ArchiLogger.LogGenericError(Strings.ErrorMobileAuthenticatorInvalidDeviceID);
 
 				return null;
@@ -228,7 +227,7 @@ namespace ArchiSteamFarm {
 				return false;
 			}
 
-			if (!HasCorrectDeviceID) {
+			if (!HasValidDeviceID) {
 				Bot.ArchiLogger.LogGenericError(Strings.ErrorMobileAuthenticatorInvalidDeviceID);
 
 				return false;
@@ -278,6 +277,26 @@ namespace ArchiSteamFarm {
 
 		internal void Init(Bot bot) => Bot = bot ?? throw new ArgumentNullException(nameof(bot));
 
+		internal static bool IsValidDeviceID(string deviceID) {
+			if (string.IsNullOrEmpty(deviceID)) {
+				ASF.ArchiLogger.LogNullError(nameof(deviceID));
+
+				return false;
+			}
+
+			// To the best of my knowledge, Steam uses android identifier even on iOS and other devices right now
+			// If we ever need to correct this, we also need to clean up other places
+			const string deviceIdentifier = "android:";
+
+			if (!deviceID.StartsWith(deviceIdentifier, StringComparison.Ordinal) || (deviceID.Length != deviceIdentifier.Length + 36)) {
+				return false;
+			}
+
+			string hash = deviceID.Substring(deviceIdentifier.Length).Replace("-", "");
+
+			return (hash.Length == 32) && Utilities.IsValidHexadecimalString(hash);
+		}
+
 		private string GenerateConfirmationHash(uint time, string tag = null) {
 			if (time == 0) {
 				Bot.ArchiLogger.LogNullError(nameof(time));
diff --git a/ArchiSteamFarm/Utilities.cs b/ArchiSteamFarm/Utilities.cs
index 90c97639e..839b79b47 100644
--- a/ArchiSteamFarm/Utilities.cs
+++ b/ArchiSteamFarm/Utilities.cs
@@ -180,17 +180,55 @@ namespace ArchiSteamFarm {
 				return false;
 			}
 
-			const byte split = 16;
-
-			for (byte i = 0; i < text.Length; i += split) {
-				string textPart = string.Join("", text.Skip(i).Take(split));
-
-				if (!ulong.TryParse(textPart, NumberStyles.HexNumber, null, out _)) {
-					return false;
-				}
+			if (text.Length % 2 != 0) {
+				return false;
 			}
 
-			return true;
+			// ulong is 64-bits wide, each hexadecimal character is 4-bits wide, so we split each 16
+			const byte split = 16;
+
+			string lastHex;
+
+			if (text.Length >= split) {
+				StringBuilder hex = new StringBuilder(split);
+
+				foreach (char character in text) {
+					hex.Append(character);
+
+					if (hex.Length < split) {
+						continue;
+					}
+
+					if (!ulong.TryParse(hex.ToString(), NumberStyles.HexNumber, null, out _)) {
+						return false;
+					}
+
+					hex.Clear();
+				}
+
+				if (hex.Length == 0) {
+					return true;
+				}
+
+				lastHex = hex.ToString();
+			} else {
+				lastHex = text;
+			}
+
+			switch (lastHex.Length) {
+				case 2:
+
+					return byte.TryParse(lastHex, NumberStyles.HexNumber, null, out _);
+				case 4:
+
+					return ushort.TryParse(lastHex, NumberStyles.HexNumber, null, out _);
+				case 8:
+
+					return uint.TryParse(lastHex, NumberStyles.HexNumber, null, out _);
+				default:
+
+					return false;
+			}
 		}
 
 		internal static int RandomNext() {