diff --git a/app-common/src/main/java/im/angry/openeuicc/util/ActivationCode.kt b/app-common/src/main/java/im/angry/openeuicc/util/ActivationCode.kt
index fd8156b..296fe22 100644
--- a/app-common/src/main/java/im/angry/openeuicc/util/ActivationCode.kt
+++ b/app-common/src/main/java/im/angry/openeuicc/util/ActivationCode.kt
@@ -8,13 +8,12 @@ data class ActivationCode(
 ) {
     companion object {
         fun fromString(input: String): ActivationCode {
-            val components = input.removePrefix("LPA:").split('$')
-                .map(String::trim).map { it.ifBlank { null } }
-            if (components.size < 2 || components[0] != "1" || components[1] == null) {
-                throw IllegalStateException("Invalid activation code format")
-            }
+            check(input.startsWith("LPA:", ignoreCase = true)) { "Invalid activation code format" }
+            val components = input.drop(4).split('$').map(String::trim).map { it.ifBlank { null } }
+            check(components.size >= 2) { "Invalid activation code format" }
+            check(components[0] == "1") { "Invalid activation code version" }
             return ActivationCode(
-                components[1]!!,
+                checkNotNull(components[1]) { "Invalid SM-DP+ address" },
                 components.getOrNull(2),
                 components.getOrNull(3),
                 components.getOrNull(4) == "1",