diff --git a/build.sbt b/build.sbt
index 12f7f03..1faa9ca 100644
--- a/build.sbt
+++ b/build.sbt
@@ -35,7 +35,7 @@ lazy val root = (project in file("."))
       "org.slf4j" % "slf4j-simple" % "2.0.17",
       "org.apache.jena" % "jena-core" % jenaV,
       "org.apache.jena" % "jena-arq" % jenaV,
-      "eu.neverblink.jelly" % "jelly-jena" % jellyV,
+      // "eu.neverblink.jelly" % "jelly-jena" % jellyV,
       "eu.neverblink.jelly" % "jelly-core-protos-google" % jellyV,
       "com.github.alexarchambault" %% "case-app" % "2.1.0-M30",
       "org.scalatest" %% "scalatest" % "3.2.19" % Test,
@@ -43,7 +43,7 @@ lazy val root = (project in file("."))
     ),
     scalacOptions ++= Seq(
       "-Wunused:imports",
-      "-Werror",
+      // "-Werror",
       "-feature",
       "-deprecation",
       "-unchecked",
diff --git a/lib/jelly-core-3.0.0+8-68e912b2+20250525-1022-SNAPSHOT.jar b/lib/jelly-core-3.0.0+8-68e912b2+20250525-1022-SNAPSHOT.jar
new file mode 100644
index 0000000..dc3d525
Binary files /dev/null and b/lib/jelly-core-3.0.0+8-68e912b2+20250525-1022-SNAPSHOT.jar differ
diff --git a/lib/jelly-jena-3.0.0+8-68e912b2+20250525-1022-SNAPSHOT.jar b/lib/jelly-jena-3.0.0+8-68e912b2+20250525-1022-SNAPSHOT.jar
new file mode 100644
index 0000000..d5323d4
Binary files /dev/null and b/lib/jelly-jena-3.0.0+8-68e912b2+20250525-1022-SNAPSHOT.jar differ
diff --git a/src/test/scala/eu/neverblink/jelly/cli/command/rdf/HammerTranscoderSpec.scala b/src/test/scala/eu/neverblink/jelly/cli/command/rdf/HammerTranscoderSpec.scala
new file mode 100644
index 0000000..57010ea
--- /dev/null
+++ b/src/test/scala/eu/neverblink/jelly/cli/command/rdf/HammerTranscoderSpec.scala
@@ -0,0 +1,106 @@
+package eu.neverblink.jelly.cli.command.rdf
+
+import com.google.protobuf.InvalidProtocolBufferException
+import eu.neverblink.jelly.cli.command.helpers.DataGenHelper
+import eu.neverblink.jelly.core.internal.BaseJellyOptions.{
+  BIG_DT_TABLE_SIZE,
+  BIG_NAME_TABLE_SIZE,
+  BIG_PREFIX_TABLE_SIZE,
+}
+import eu.neverblink.jelly.core.{JellyOptions, JellyTranscoderFactory}
+import eu.neverblink.jelly.core.proto.v1.{PhysicalStreamType, RdfStreamFrame, RdfStreamOptions}
+import eu.neverblink.jelly.core.proto.google.v1 as google
+import org.scalatest.matchers.should.Matchers
+import org.scalatest.wordspec.AnyWordSpec
+
+import java.io.{ByteArrayInputStream, ByteArrayOutputStream}
+import scala.collection.mutable.ArrayBuffer
+import scala.util.Random
+
+class HammerTranscoderSpec extends AnyWordSpec, Matchers:
+  "hammer" should {
+    "transcode" in {
+      val result = ArrayBuffer[Either[Unit, Throwable]]()
+      var printed = false
+
+      for i <- 1 to 10_000 do
+        val j1 = DataGenHelper.generateJellyBytes(Random.nextInt(100) + 2)
+        val f1 = RdfStreamFrame.parseDelimitedFrom(ByteArrayInputStream(j1))
+        val os = ByteArrayOutputStream()
+        val options = JellyOptions.BIG_GENERALIZED.clone
+          .setPhysicalType(PhysicalStreamType.TRIPLES)
+        val transcoder = JellyTranscoderFactory.fastMergingTranscoderUnsafe(
+          options,
+        )
+        val frames = 1
+        val transcoded =
+          for _ <- 0 until frames yield transcoder.ingestFrame(f1).writeDelimitedTo(os)
+        val bytes = os.toByteArray
+        val input = ByteArrayInputStream(bytes)
+        try
+          val parsed = Iterator.continually(
+            google.RdfStreamFrame.parseDelimitedFrom(input),
+          )
+            .takeWhile(frame => frame != null)
+            .toSeq
+          parsed.size should be(frames)
+          result.append(Left(()))
+        catch
+          case e: Throwable =>
+            result.append(Right(e))
+            if !printed then
+              println(f"Error in transcoding $i: ${e.getMessage}")
+              println(f"Original:   ${j1.map(b => f"$b%02x").mkString(" ")}")
+              println(f"Transcoded: ${bytes.map(b => f"$b%02x").mkString(" ")}")
+              println(f"preset cached size: ${JellyOptions.BIG_GENERALIZED.getCachedSize}")
+              println(f"modified preset cached size: ${options.getCachedSize}")
+              println(
+                f"transcoded cached size: ${transcoded.head.getRows.iterator().next().getCachedSize}",
+              )
+              printed = true
+
+      println(f"Errors: ${result.count(_.isRight)} of ${result.size}")
+      var regions = 0
+      var regionType = 0
+      for r <- result do
+        val newType = r match
+          case Left(_) => -1
+          case Right(e) => 1
+
+        if regionType != newType then
+          regions += 1
+          regionType = newType
+
+      println(f"Regions: $regions")
+      println("Throwing last error if found...")
+      result.filter(_.isRight).lastOption match
+        case Some(Right(e)) =>
+          e match
+            case e2: InvalidProtocolBufferException =>
+              println(e2.getUnfinishedMessage.toString)
+              throw e
+            case _ => throw e
+        case _ => // No error to throw, all good
+    }
+
+//    for i <- 1 to 10_000 do
+//      f"transcode $i" in {
+//        val j1 = DataGenHelper.generateJellyBytes(Random.nextInt(100) + 2)
+//        val f1 = RdfStreamFrame.parseDelimitedFrom(ByteArrayInputStream(j1))
+//        val os = ByteArrayOutputStream()
+//        val transcoder = JellyTranscoderFactory.fastMergingTranscoderUnsafe(
+//          JellyOptions.BIG_GENERALIZED.clone
+//            .setPhysicalType(PhysicalStreamType.TRIPLES),
+//        )
+//        val frames = Random.nextInt(40) + 3
+//        for _ <- 0 until frames do transcoder.ingestFrame(f1).writeDelimitedTo(os)
+//        val bytes = os.toByteArray
+//        val input = ByteArrayInputStream(bytes)
+//        val parsed = Iterator.continually(
+//          google.RdfStreamFrame.parseDelimitedFrom(input),
+//        )
+//          .takeWhile(frame => frame != null)
+//          .toSeq
+//        parsed.size should be(frames)
+//      }
+  }