diff --git a/src/main/kotlin/app/revanced/patcher/signature/MethodSignature.kt b/src/main/kotlin/app/revanced/patcher/signature/MethodSignature.kt
index f1a46f87..b349954b 100644
--- a/src/main/kotlin/app/revanced/patcher/signature/MethodSignature.kt
+++ b/src/main/kotlin/app/revanced/patcher/signature/MethodSignature.kt
@@ -10,13 +10,14 @@ import org.jf.dexlib2.Opcode
  * @param accessFlags The access flags of the method.
  * @param methodParameters The parameters of the method.
  * @param opcodes The list of opcodes of the method.
+ * A `null` opcode is equals to an unknown opcode.
  */
 class MethodSignature(
     val metadata: MethodSignatureMetadata,
     internal val returnType: String?,
     internal val accessFlags: Int?,
     internal val methodParameters: Iterable<String>?,
-    internal val opcodes: Iterable<Opcode>?
+    internal val opcodes: Iterable<Opcode?>?
 ) {
     /**
      * The result of the signature
diff --git a/src/main/kotlin/app/revanced/patcher/signature/resolver/SignatureResolver.kt b/src/main/kotlin/app/revanced/patcher/signature/resolver/SignatureResolver.kt
index 3d55e845..8183f17b 100644
--- a/src/main/kotlin/app/revanced/patcher/signature/resolver/SignatureResolver.kt
+++ b/src/main/kotlin/app/revanced/patcher/signature/resolver/SignatureResolver.kt
@@ -93,7 +93,11 @@ internal class SignatureResolver(
                 while (instructionIndex + patternIndex < count) {
                     val originalOpcode = instructions.elementAt(instructionIndex + patternIndex).opcode
                     val patternOpcode = pattern.elementAt(patternIndex)
-                    if (originalOpcode != patternOpcode && currentThreshold-- == 0) break
+                    if (
+                        patternOpcode != null && // unknown opcode
+                        originalOpcode != patternOpcode &&
+                        currentThreshold-- == 0
+                    ) break
                     if (++patternIndex < size) continue
 
                     val result = PatternScanResult(instructionIndex, instructionIndex + patternIndex)
@@ -125,7 +129,10 @@ internal class SignatureResolver(
             for ((patternIndex, originalIndex) in (scanResult.startIndex until scanResult.endIndex).withIndex()) {
                 val originalOpcode = instructions.elementAt(originalIndex).opcode
                 val patternOpcode = pattern.elementAt(patternIndex)
-                if (originalOpcode != patternOpcode) {
+                if (
+                    patternOpcode != null && // unknown opcode
+                    originalOpcode != patternOpcode
+                ) {
                     this.add(
                         PatternScanMethod.Fuzzy.Warning(
                             originalOpcode, patternOpcode,