diff --git a/app-common/src/main/java/im/angry/openeuicc/vendored/estkme.kt b/app-common/src/main/java/im/angry/openeuicc/vendored/estkme.kt
index 86132be..b6efab1 100644
--- a/app-common/src/main/java/im/angry/openeuicc/vendored/estkme.kt
+++ b/app-common/src/main/java/im/angry/openeuicc/vendored/estkme.kt
@@ -4,7 +4,6 @@ import android.util.Log
 import im.angry.openeuicc.core.ApduInterfaceAtrProvider
 import im.angry.openeuicc.util.TAG
 import im.angry.openeuicc.util.decodeHex
-import im.angry.openeuicc.util.encodeHex
 import net.typeblog.lpac_jni.ApduInterface
 
 data class ESTKmeInfo(
@@ -14,11 +13,19 @@ data class ESTKmeInfo(
     val skuName: String?,
 )
 
-fun isESTKmeATR(atr: ByteArray?): Boolean =
-    atr != null && atr.encodeHex().contains("estk.me".encodeToByteArray().encodeHex())
+fun isESTKmeATR(iface: ApduInterface): Boolean {
+    if (iface !is ApduInterfaceAtrProvider) return false
+    val atr = iface.atr ?: return false
+    val fpr = "estk.me".encodeToByteArray()
+    for (index in atr.indices) {
+        if (atr.size - index < fpr.size) break
+        if (atr.sliceArray(index until index + fpr.size).contentEquals(fpr)) return true
+    }
+    return false
+}
 
 fun getESTKmeInfo(iface: ApduInterface): ESTKmeInfo? {
-    if (!isESTKmeATR((iface as ApduInterfaceAtrProvider?)?.atr)) return null
+    if (!isESTKmeATR(iface)) return null
     fun decode(b: ByteArray): String? {
         if (b.size < 2) return null
         if (b[b.size - 2] != 0x90.toByte() || b[b.size - 1] != 0x00.toByte()) return null