diff --git a/beacon_chain/beacon_node_light_client.nim b/beacon_chain/beacon_node_light_client.nim
index a2038a2a7..b77f16a4f 100644
--- a/beacon_chain/beacon_node_light_client.nim
+++ b/beacon_chain/beacon_node_light_client.nim
@@ -48,7 +48,9 @@ proc initLightClient*(
         dag = node.dag.head.bid,
         wallSlot = node.currentSlot
       withBlck(signedBlock):
-        when stateFork >= BeaconStateFork.Bellatrix:
+        when stateFork == BeaconStateFork.EIP4844:
+          debugRaiseAssert $eip4844ImplementationMissing & ": beacon_node_light_client.nim:initLightClient"
+        elif stateFork >= BeaconStateFork.Bellatrix:
           if blck.message.is_execution_block:
             template payload(): auto = blck.message.body.execution_payload
 
diff --git a/beacon_chain/era_db.nim b/beacon_chain/era_db.nim
index da2987a26..b0f9f14fe 100644
--- a/beacon_chain/era_db.nim
+++ b/beacon_chain/era_db.nim
@@ -385,9 +385,9 @@ iterator getBlockIds*(
       if not getPartialState(db, historical_roots, stateSlot, state[]):
         state = nil # No `return` in iterators
     of BeaconStateFork.Capella:
-      raiseAssert $capellaImplementationMissing
+      debugRaiseAssert $capellaImplementationMissing & ": era_db.nim: getBlockIds"
     of BeaconStateFork.EIP4844:
-      raiseAssert $eip4844ImplementationMissing
+      debugRaiseAssert $eip4844ImplementationMissing & ": era_db.nim: getBlockIds"
 
     if state == nil:
       break
diff --git a/beacon_chain/gossip_processing/block_processor.nim b/beacon_chain/gossip_processing/block_processor.nim
index 2333fe676..d521d6cb0 100644
--- a/beacon_chain/gossip_processing/block_processor.nim
+++ b/beacon_chain/gossip_processing/block_processor.nim
@@ -290,6 +290,17 @@ proc newExecutionPayload*(
     error "newPayload failed", msg = err.msg
     return Opt.none PayloadExecutionStatus
 
+# TODO investigate why this seems to allow compilation even though it doesn't
+# directly address eip4844.ExecutionPayload when complaint was that it didn't
+# know about "eip4844"
+from ../spec/datatypes/eip4844 import SignedBeaconBlock, asTrusted, shortLog
+
+proc newExecutionPayload*(
+    eth1Monitor: Eth1Monitor,
+    executionPayload: eip4844.ExecutionPayload):
+    Future[Opt[PayloadExecutionStatus]] {.async.} =
+  debugRaiseAssert $eip4844ImplementationMissing & ": block_processor.nim:newExecutionPayload"
+
 proc getExecutionValidity(
     eth1Monitor: Eth1Monitor,
     blck: phase0.SignedBeaconBlock | altair.SignedBeaconBlock):
@@ -332,6 +343,12 @@ proc getExecutionValidity(
     error "getExecutionValidity: newPayload failed", err = err.msg
     return NewPayloadStatus.noResponse
 
+proc getExecutionValidity(
+    eth1Monitor: Eth1Monitor,
+    blck: eip4844.SignedBeaconBlock):
+    Future[NewPayloadStatus] {.async.} =
+  debugRaiseAssert $eip4844ImplementationMissing & ": block_processor.nim:getExecutionValidity"
+
 proc storeBlock*(
     self: ref BlockProcessor, src: MsgSource, wallTime: BeaconTime,
     signedBlock: ForkySignedBeaconBlock, queueTick: Moment = Moment.now(),
diff --git a/beacon_chain/gossip_processing/gossip_validation.nim b/beacon_chain/gossip_processing/gossip_validation.nim
index fa8db91a3..7ec329fc1 100644
--- a/beacon_chain/gossip_processing/gossip_validation.nim
+++ b/beacon_chain/gossip_processing/gossip_validation.nim
@@ -387,6 +387,15 @@ proc validateBeaconBlock*(
 
   ok()
 
+from ../spec/datatypes/eip4844 import SignedBeaconBlock
+
+proc validateBeaconBlock*(
+    dag: ChainDAGRef, quarantine: ref Quarantine,
+    signed_beacon_block: eip4844.SignedBeaconBlock,
+    wallTime: BeaconTime, flags: UpdateFlags): Result[void, ValidationError] =
+  debugRaiseAssert $eip4844ImplementationMissing & ": gossip_validation.nim: validateBeaconBlock not how EIP4844 works anymore"
+  err(default(ValidationError))
+
 # https://github.com/ethereum/consensus-specs/blob/v1.1.9/specs/phase0/p2p-interface.md#beacon_attestation_subnet_id
 proc validateAttestation*(
     pool: ref AttestationPool,
diff --git a/beacon_chain/networking/eth2_network.nim b/beacon_chain/networking/eth2_network.nim
index 8dd800341..494ae1d9e 100644
--- a/beacon_chain/networking/eth2_network.nim
+++ b/beacon_chain/networking/eth2_network.nim
@@ -2632,9 +2632,22 @@ proc broadcastBeaconBlock*(
   let topic = getBeaconBlocksTopic(node.forkDigests.capella)
   node.broadcast(topic, blck)
 
+from ../spec/datatypes/eip4844 import SignedBeaconBlock
+
+proc broadcastBeaconBlock*(
+    node: Eth2Node, blck: eip4844.SignedBeaconBlock): Future[SendResult] =
+  debugRaiseAssert $eip4844ImplementationMissing & ": eth2_network.nim:broadcastBeaconBlock EIP4844 uses different approach (1)"
+
 proc broadcastBeaconBlock*(
     node: Eth2Node, forked: ForkedSignedBeaconBlock): Future[SendResult] =
-  withBlck(forked): node.broadcastBeaconBlock(blck)
+  withBlck(forked):
+    when stateFork == BeaconStateFork.EIP4844:
+      debugRaiseAssert $eip4844ImplementationMissing & ": eth2_network.nim:broadcastBeaconBlock EIP4844 uses different approach (2)"
+      let f = newFuture[SendResult]()
+      f.fail(new CatchableError)
+      f
+    else:
+      node.broadcastBeaconBlock(blck)
 
 proc broadcastSyncCommitteeMessage*(
     node: Eth2Node, msg: SyncCommitteeMessage,
diff --git a/beacon_chain/rpc/rest_utils.nim b/beacon_chain/rpc/rest_utils.nim
index c908b7d1b..6249af128 100644
--- a/beacon_chain/rpc/rest_utils.nim
+++ b/beacon_chain/rpc/rest_utils.nim
@@ -301,11 +301,8 @@ proc getBlockRefOptimistic*(node: BeaconNode, blck: BlockRef): bool =
   case blck.kind
   of BeaconBlockFork.Phase0, BeaconBlockFork.Altair:
     false
-  of BeaconBlockFork.Bellatrix, BeaconBlockFork.Capella:
+  of BeaconBlockFork.Bellatrix, BeaconBlockFork.Capella, BeaconBlockFork.EIP4844:
     node.dag.is_optimistic(blck.root)
-  of BeaconBlockFork.EIP4844:
-    if true: raiseAssert $eip4844ImplementationMissing
-    true
 
 const
   jsonMediaType* = MediaType.init("application/json")
diff --git a/beacon_chain/spec/datatypes/base.nim b/beacon_chain/spec/datatypes/base.nim
index 65008f05d..2f38e3f31 100644
--- a/beacon_chain/spec/datatypes/base.nim
+++ b/beacon_chain/spec/datatypes/base.nim
@@ -984,3 +984,6 @@ func checkForkConsistency*(cfg: RuntimeConfig) =
 const capellaImplementationMissing* = false
 
 const eip4844ImplementationMissing* = false
+
+#template debugRaiseAssert*(x: string) = raiseAssert x
+template debugRaiseAssert*(x: string) = discard
diff --git a/beacon_chain/spec/eth2_apis/eth2_rest_serialization.nim b/beacon_chain/spec/eth2_apis/eth2_rest_serialization.nim
index e9df0f5e7..b393714dd 100644
--- a/beacon_chain/spec/eth2_apis/eth2_rest_serialization.nim
+++ b/beacon_chain/spec/eth2_apis/eth2_rest_serialization.nim
@@ -1160,7 +1160,8 @@ proc writeValue*[
     writer.writeField("version", forkIdentifier "capella")
     writer.writeField("data", value.capellaData)
   of BeaconBlockFork.EIP4844:
-    raiseAssert $eip4844ImplementationMissing
+    writer.writeField("version", forkIdentifier "eip4844")
+    writer.writeField("data", value.eip4844Data)
   writer.endRecord()
 
 ## RestPublishedBeaconBlockBody
@@ -1591,7 +1592,8 @@ proc writeValue*(writer: var JsonWriter[RestJson],
     writer.writeField("version", "capella")
     writer.writeField("data", value.capellaData)
   of BeaconBlockFork.EIP4844:
-    raiseAssert $eip4844ImplementationMissing
+    writer.writeField("version", "eip4844")
+    writer.writeField("data", value.eip4844Data)
   writer.endRecord()
 
 # ForkedHashedBeaconState is used where a `ForkedBeaconState` normally would
diff --git a/beacon_chain/spec/forks.nim b/beacon_chain/spec/forks.nim
index 9ffa2c4ff..ce6b89697 100644
--- a/beacon_chain/spec/forks.nim
+++ b/beacon_chain/spec/forks.nim
@@ -686,8 +686,8 @@ template withBlck*(
     template blck: untyped {.inject.} = x.capellaData
     body
   of BeaconBlockFork.EIP4844:
-    const stateFork {.inject, used.} = BeaconStateFork.Capella
-    template blck: untyped {.inject.} = x.capellaData
+    const stateFork {.inject, used.} = BeaconStateFork.EIP4844
+    template blck: untyped {.inject.} = x.eip4844Data
     body
 
 func proposer_index*(x: ForkedBeaconBlock): uint64 =
diff --git a/beacon_chain/spec/state_transition.nim b/beacon_chain/spec/state_transition.nim
index c00522abb..a044cdce7 100644
--- a/beacon_chain/spec/state_transition.nim
+++ b/beacon_chain/spec/state_transition.nim
@@ -584,7 +584,7 @@ proc makeBeaconBlock*[T: bellatrix.ExecutionPayload | capella.ExecutionPayload](
         BeaconStateFork.Bellatrix, BeaconStateFork.Capella:
       raiseAssert "Attempt to use EIP4844 payload with non-EIP4844 state"
     of BeaconStateFork.EIP4844:
-      raiseAssert $eip4844ImplementationMissing & ": state_transition"
+      debugRaiseAssert $eip4844ImplementationMissing & ": state_transition"
 
 # workaround for https://github.com/nim-lang/Nim/issues/20900 rather than have
 # these be default arguments
diff --git a/beacon_chain/trusted_node_sync.nim b/beacon_chain/trusted_node_sync.nim
index fd1ae4359..a7823e025 100644
--- a/beacon_chain/trusted_node_sync.nim
+++ b/beacon_chain/trusted_node_sync.nim
@@ -46,6 +46,8 @@ proc fetchDepositSnapshot(client: RestClientRef):
 
   return ok snapshot
 
+from ./spec/datatypes/eip4844 import asSigVerified, shortLog
+
 proc doTrustedNodeSync*(
     cfg: RuntimeConfig,
     databaseDir: string,
diff --git a/beacon_chain/validator_client/api.nim b/beacon_chain/validator_client/api.nim
index a6abb9ca7..3975ba9f5 100644
--- a/beacon_chain/validator_client/api.nim
+++ b/beacon_chain/validator_client/api.nim
@@ -1688,7 +1688,10 @@ proc publishBlock*(
         of BeaconBlockFork.Capella:
           publishBlock(it, data.capellaData)
         of BeaconBlockFork.EIP4844:
-          raiseAssert $eip4844ImplementationMissing
+          debugRaiseAssert $eip4844ImplementationMissing & ": validator_client/api.nim:publishBlock (1)"
+          let f = newFuture[RestPlainResponse]("")
+          f.fail(new RestError)
+          f
 
       do:
         if apiResponse.isErr():
@@ -1740,7 +1743,10 @@ proc publishBlock*(
       of BeaconBlockFork.Capella:
         publishBlock(it, data.capellaData)
       of BeaconBlockFork.EIP4844:
-        raiseAssert $eip4844ImplementationMissing
+        debugRaiseAssert $eip4844ImplementationMissing & ": validator_client/api.nim:publishBlock (2)"
+        let f = newFuture[RestPlainResponse]("")
+        f.fail(new RestError)
+        f
     do:
       if apiResponse.isErr():
         debug ErrorMessage, endpoint = node, error = apiResponse.error()
@@ -1887,7 +1893,10 @@ proc publishBlindedBlock*(
         of BeaconBlockFork.Capella:
           publishBlindedBlock(it, data.capellaData)
         of BeaconBlockFork.EIP4844:
-          raiseAssert $eip4844ImplementationMissing
+          debugRaiseAssert $eip4844ImplementationMissing & ": validator_client/api.nim:publishBlindedBlock (1)"
+          let f = newFuture[RestPlainResponse]("")
+          f.fail(new RestError)
+          f
       do:
         if apiResponse.isErr():
           debug ErrorMessage, endpoint = node, error = apiResponse.error()
@@ -1938,7 +1947,10 @@ proc publishBlindedBlock*(
       of BeaconBlockFork.Capella:
         publishBlindedBlock(it, data.capellaData)
       of BeaconBlockFork.EIP4844:
-        raiseAssert $eip4844ImplementationMissing
+        debugRaiseAssert $eip4844ImplementationMissing & ": validator_client/api.nim:publishBlindedBlock (2)"
+        let f = newFuture[RestPlainResponse]("")
+        f.fail(new RestError)
+        f
     do:
       if apiResponse.isErr():
         debug ErrorMessage, endpoint = node, error = apiResponse.error()
diff --git a/beacon_chain/validators/validator_duties.nim b/beacon_chain/validators/validator_duties.nim
index 48a5eb0a1..12f67697e 100644
--- a/beacon_chain/validators/validator_duties.nim
+++ b/beacon_chain/validators/validator_duties.nim
@@ -321,7 +321,8 @@ proc get_execution_payload[EP](
       asConsensusExecutionPayload(
         await execution_engine.getPayload(payload_id.get))
     else:
-      raiseAssert $capellaImplementationMissing & ": implement getPayload V2"
+      debugRaiseAssert $capellaImplementationMissing & ": implement getPayload V2"
+      default(EP)
 
 proc getFeeRecipient(node: BeaconNode,
                      pubkey: ValidatorPubKey,
@@ -795,6 +796,8 @@ proc makeBlindedBeaconBlockForHeadAndSlot*(
   return ok constructPlainBlindedBlock[BlindedBeaconBlock](
     forkedBlck, executionPayloadHeader)
 
+from ../spec/datatypes/eip4844 import shortLog
+
 proc proposeBlock(node: BeaconNode,
                   validator: AttachedValidator,
                   validator_index: ValidatorIndex,
@@ -895,6 +898,9 @@ proc proposeBlock(node: BeaconNode,
         elif blck is capella.BeaconBlock:
           capella.SignedBeaconBlock(
             message: blck, signature: signature, root: blockRoot)
+        elif blck is eip4844.BeaconBlock:
+          eip4844.SignedBeaconBlock(
+            message: blck, signature: signature, root: blockRoot)
         else:
           static: doAssert "Unknown SignedBeaconBlock type"
       newBlockRef =
diff --git a/beacon_chain/validators/validator_monitor.nim b/beacon_chain/validators/validator_monitor.nim
index 8acd76eb3..68627bc82 100644
--- a/beacon_chain/validators/validator_monitor.nim
+++ b/beacon_chain/validators/validator_monitor.nim
@@ -725,6 +725,8 @@ proc registerAttestationInBlock*(
       update_if_lt(
         epochSummary.attestation_min_block_inclusion_distance, inclusion_lag)
 
+from ../spec/datatypes/eip4844 import shortLog
+
 proc registerBeaconBlock*(
     self: var ValidatorMonitor,
     src: MsgSource,
diff --git a/beacon_chain/validators/validator_pool.nim b/beacon_chain/validators/validator_pool.nim
index c078d48e1..2a3c5393a 100644
--- a/beacon_chain/validators/validator_pool.nim
+++ b/beacon_chain/validators/validator_pool.nim
@@ -389,7 +389,9 @@ proc getBlockSignature*(v: AttachedValidator, fork: Fork,
                 kind: BeaconBlockFork.Capella,
                 capellaData: blck.capellaData.toBeaconBlockHeader)
             of BeaconBlockFork.EIP4844:
-              raiseAssert $eip4844ImplementationMissing
+              Web3SignerForkedBeaconBlock(
+                kind: BeaconBlockFork.EIP4844,
+                eip4844Data: blck.eip4844Data.toBeaconBlockHeader)
 
           request = Web3SignerRequest.init(
             fork, genesis_validators_root, web3SignerBlock)
@@ -422,7 +424,9 @@ proc getBlockSignature*(v: AttachedValidator, fork: Fork,
                 kind: BeaconBlockFork.Capella,
                 capellaData: blck.capellaData.toBeaconBlockHeader)
             of BeaconBlockFork.EIP4844:
-              raiseAssert $eip4844ImplementationMissing
+              Web3SignerForkedBeaconBlock(
+                kind: BeaconBlockFork.EIP4844,
+                eip4844Data: blck.eip4844Data.toBeaconBlockHeader)
 
           request = Web3SignerRequest.init(
             fork, genesis_validators_root, web3SignerBlock)
diff --git a/ncli/ncli_db.nim b/ncli/ncli_db.nim
index 98734ab42..e27673c6e 100644
--- a/ncli/ncli_db.nim
+++ b/ncli/ncli_db.nim
@@ -1000,7 +1000,7 @@ proc cmdValidatorDb(conf: DbConf, cfg: RuntimeConfig) =
         withState(tmpState[]):
           var stateData = newClone(forkyState.data)
           when stateFork == BeaconStateFork.EIP4844:
-            raiseAssert $eip4844ImplementationMissing & ": ncli_db.nim:cmdValidatorDb"
+            debugRaiseAssert $eip4844ImplementationMissing & ": ncli_db.nim:cmdValidatorDb"
           else:
             rewardsAndPenalties.collectEpochRewardsAndPenalties(
               stateData[], cache, cfg, flags)
diff --git a/tests/consensus_spec/altair/test_fixture_fork.nim b/tests/consensus_spec/altair/test_fixture_fork.nim
index b7ebfa4f7..acf79e6bc 100644
--- a/tests/consensus_spec/altair/test_fixture_fork.nim
+++ b/tests/consensus_spec/altair/test_fixture_fork.nim
@@ -8,8 +8,6 @@
 {.used.}
 
 import
-  # Standard library
-  os,
   # Beacon chain internals
   ../../../beacon_chain/spec/[beaconstate, helpers],
   ../../../beacon_chain/spec/datatypes/[phase0, altair],
@@ -18,6 +16,8 @@ import
   ../fixtures_utils,
   ../../helpers/debug_state
 
+from std/os import walkDir, `/`
+
 const OpForkDir = SszTestsDir/const_preset/"altair"/"fork"/"fork"/"pyspec_tests"
 
 proc runTest(identifier: string) =
diff --git a/tests/consensus_spec/bellatrix/test_fixture_fork.nim b/tests/consensus_spec/bellatrix/test_fixture_fork.nim
index f68fa33f0..ec90541bb 100644
--- a/tests/consensus_spec/bellatrix/test_fixture_fork.nim
+++ b/tests/consensus_spec/bellatrix/test_fixture_fork.nim
@@ -8,8 +8,6 @@
 {.used.}
 
 import
-  # Standard library
-  os,
   # Beacon chain internals
   ../../../beacon_chain/spec/[beaconstate, helpers],
   ../../../beacon_chain/spec/datatypes/[altair, bellatrix],
@@ -18,6 +16,8 @@ import
   ../fixtures_utils,
   ../../helpers/debug_state
 
+from std/os import walkDir, `/`
+
 const OpForkDir = SszTestsDir/const_preset/"bellatrix"/"fork"/"fork"/"pyspec_tests"
 
 proc runTest(identifier: string) =
diff --git a/tests/consensus_spec/bellatrix/test_fixture_operations.nim b/tests/consensus_spec/bellatrix/test_fixture_operations.nim
index 69b46df76..2c8800862 100644
--- a/tests/consensus_spec/bellatrix/test_fixture_operations.nim
+++ b/tests/consensus_spec/bellatrix/test_fixture_operations.nim
@@ -8,8 +8,6 @@
 {.used.}
 
 import
-  # Standard library
-  std/[os, sequtils, sets, strutils],
   # Utilities
   chronicles,
   unittest2,
@@ -22,6 +20,10 @@ import
   ../fixtures_utils,
   ../../helpers/debug_state
 
+from std/os import fileExists, walkDir, `/`
+from std/sequtils import mapIt, toSeq
+from std/strutils import contains
+
 const
   OpDir                 = SszTestsDir/const_preset/"bellatrix"/"operations"
   OpAttestationsDir     = OpDir/"attestation"
diff --git a/tests/consensus_spec/bellatrix/test_fixture_ssz_consensus_objects.nim b/tests/consensus_spec/bellatrix/test_fixture_ssz_consensus_objects.nim
index 8136552f2..b609a35cb 100644
--- a/tests/consensus_spec/bellatrix/test_fixture_ssz_consensus_objects.nim
+++ b/tests/consensus_spec/bellatrix/test_fixture_ssz_consensus_objects.nim
@@ -8,9 +8,6 @@
 {.used.}
 
 import
-  # Standard library
-  os, strutils, streams, strformat,
-  macros, sets,
   # Third-party
   yaml,
   # Beacon chain internals
@@ -20,6 +17,11 @@ import
   # Test utilities
   ../../testutil, ../fixtures_utils
 
+from std/os import dirExists, pcDir, walkDir, `/`
+from std/streams import close, openFileStream
+from std/strformat import `&`
+from std/strutils import toLowerAscii
+
 # SSZ tests of consensus objects (minimal/mainnet preset specific)
 
 # Parsing definitions
diff --git a/tests/consensus_spec/capella/test_fixture_transition.nim b/tests/consensus_spec/capella/test_fixture_transition.nim
index 0834ad36f..1b7d75802 100644
--- a/tests/consensus_spec/capella/test_fixture_transition.nim
+++ b/tests/consensus_spec/capella/test_fixture_transition.nim
@@ -10,8 +10,6 @@
 import
   chronicles,
   yaml,
-  # Standard library
-  std/[os, sequtils, strutils],
   # Status internal
   faststreams, streams,
   # Beacon chain internals
@@ -21,6 +19,9 @@ import
   ../../testutil,
   ../fixtures_utils
 
+from std/os import walkDir, walkPattern, `/`
+from std/sequtils import toSeq
+
 const
   TransitionDir = SszTestsDir/const_preset/"capella"/"transition"/"core"/"pyspec_tests"