diff --git a/app/build.gradle b/app/build.gradle
index 8e4771d2..2e40a77f 100644
--- a/app/build.gradle
+++ b/app/build.gradle
@@ -20,7 +20,7 @@ android {
         minSdkVersion 16
         targetSdkVersion 29
         versionCode 57
-        versionName "4.21"
+        versionName "4.21-hotfix1"
         testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
         multiDexEnabled true
         vectorDrawables.useSupportLibrary = true
diff --git a/app/release/output-metadata.json b/app/release/output-metadata.json
index c94127f9..37dd8585 100644
--- a/app/release/output-metadata.json
+++ b/app/release/output-metadata.json
@@ -12,7 +12,7 @@
       "filters": [],
       "properties": [],
       "versionCode": 57,
-      "versionName": "4.21",
+      "versionName": "4.21-hotfix1",
       "enabled": true,
       "outputFile": "app-release.apk"
     }
diff --git a/libpupil/src/main/java/xyz/quaver/hitomi/common.kt b/libpupil/src/main/java/xyz/quaver/hitomi/common.kt
index 889950e2..bbbff1ac 100644
--- a/libpupil/src/main/java/xyz/quaver/hitomi/common.kt
+++ b/libpupil/src/main/java/xyz/quaver/hitomi/common.kt
@@ -58,15 +58,17 @@ fun subdomainFromURL(url: String, base: String? = null) : String {
     val r = Regex("""/[0-9a-f]/([0-9a-f]{2})/""")
     val m = r.find(url) ?: return retval
 
-    var g = m.groupValues[1].toIntOrNull(b) ?: return retval
+    var g = m.groupValues[1].toIntOrNull(b)
 
-    when {
-        g < 0x30 -> numberOfFrontends = 2
-        g < 0x09 -> g = 1
+    if (g != null) {
+        if (g < 0x30)
+            numberOfFrontends = 2
+        if (g < 0x09)
+            g = 1
+
+        retval = subdomainFromGalleryID(g, numberOfFrontends) + retval
     }
 
-    retval = subdomainFromGalleryID(g, numberOfFrontends) + retval
-
     return retval
 }
 
diff --git a/libpupil/src/test/java/xyz/quaver/hitomi/UnitTest.kt b/libpupil/src/test/java/xyz/quaver/hitomi/UnitTest.kt
index d368cc41..f282cd6b 100644
--- a/libpupil/src/test/java/xyz/quaver/hitomi/UnitTest.kt
+++ b/libpupil/src/test/java/xyz/quaver/hitomi/UnitTest.kt
@@ -82,9 +82,9 @@ class UnitTest {
 
     @Test
     fun test_getImages() {
-        val reader = getReader(1702206)
+        val reader = getReader(1702001)
 
-        print(urlFromUrlFromHash(1702206, reader.galleryInfo.files.first(), "webp"))
+        print(urlFromUrlFromHash(1702001, reader.galleryInfo.files[15], "webp"))
     }
 
     @Test