diff --git a/.github/workflows/local-testnet.yml b/.github/workflows/local-testnet.yml
index 7bd8b40d76..5cffb4e2fd 100644
--- a/.github/workflows/local-testnet.yml
+++ b/.github/workflows/local-testnet.yml
@@ -20,7 +20,7 @@ jobs:
 
       - name: Build Docker image
         run: |
-          docker build --build-arg FEATURES=portable -t lighthouse:local .
+          docker build --build-arg FEATURES=portable,spec-minimal -t lighthouse:local .
           docker save lighthouse:local -o lighthouse-docker.tar
 
       - name: Upload Docker image artifact
@@ -213,6 +213,49 @@ jobs:
             scripts/local_testnet/logs
           retention-days: 3
 
+  # Test syncing from genesis on a local testnet. Aims to cover forward syncing both short and long distances.
+  genesis-sync-test:
+    name: genesis-sync-test-${{ matrix.fork }}-${{ matrix.offline_secs }}s
+    runs-on: ubuntu-latest
+    needs: dockerfile-ubuntu
+    if: contains(github.event.pull_request.labels.*.name, 'syncing')
+    strategy:
+      matrix:
+        fork: [electra, fulu]
+        offline_secs: [120, 300]
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Install Kurtosis
+        run: |
+          echo "deb [trusted=yes] https://apt.fury.io/kurtosis-tech/ /" | sudo tee /etc/apt/sources.list.d/kurtosis.list
+          sudo apt update
+          sudo apt install -y kurtosis-cli
+          kurtosis analytics disable
+
+      - name: Download Docker image artifact
+        uses: actions/download-artifact@v4
+        with:
+          name: lighthouse-docker
+          path: .
+
+      - name: Load Docker image
+        run: docker load -i lighthouse-docker.tar
+
+      - name: Run the genesis sync test script
+        run: |
+          ./genesis-sync.sh "sync-${{ matrix.fork }}-${{ matrix.offline_secs }}s" "genesis-sync-config-${{ matrix.fork }}.yaml" "${{ matrix.fork }}" "${{ matrix.offline_secs }}"
+        working-directory: scripts/tests
+
+      - name: Upload logs artifact
+        if: always()
+        uses: actions/upload-artifact@v4
+        with:
+          name: logs-genesis-sync-${{ matrix.fork }}-${{ matrix.offline_secs }}s
+          path: |
+            scripts/local_testnet/logs
+          retention-days: 3
+
   # This job succeeds ONLY IF all others succeed. It is used by the merge queue to determine whether
   # a PR is safe to merge. New jobs should be added here.
   local-testnet-success:
@@ -228,5 +271,5 @@ jobs:
       - uses: actions/checkout@v4
       - name: Check that success job is dependent on all others
         run: |
-          exclude_jobs='checkpoint-sync-test'
+          exclude_jobs='checkpoint-sync-test|genesis-sync-test'
           ./scripts/ci/check-success-job.sh ./.github/workflows/local-testnet.yml local-testnet-success "$exclude_jobs" 
diff --git a/scripts/local_testnet/start_local_testnet.sh b/scripts/local_testnet/start_local_testnet.sh
index 8e8859ca0e..442e6fd98d 100755
--- a/scripts/local_testnet/start_local_testnet.sh
+++ b/scripts/local_testnet/start_local_testnet.sh
@@ -81,7 +81,7 @@ fi
 if [ "$BUILD_IMAGE" = true ]; then
     echo "Building Lighthouse Docker image."
     ROOT_DIR="$SCRIPT_DIR/../.."
-    docker build --build-arg FEATURES=portable -f $ROOT_DIR/Dockerfile -t $LH_IMAGE_NAME $ROOT_DIR
+    docker build --build-arg FEATURES=portable,spec-minimal -f $ROOT_DIR/Dockerfile -t $LH_IMAGE_NAME $ROOT_DIR
 else
     echo "Not rebuilding Lighthouse Docker image."
 fi
diff --git a/scripts/tests/genesis-sync-config-electra.yaml b/scripts/tests/genesis-sync-config-electra.yaml
new file mode 100644
index 0000000000..153f754c94
--- /dev/null
+++ b/scripts/tests/genesis-sync-config-electra.yaml
@@ -0,0 +1,22 @@
+# Kurtosis config file for testing sync on a local devnet.
+participants:
+  - cl_type: lighthouse
+    cl_image: lighthouse:local
+    count: 2
+  # nodes without validators, used for testing sync.
+  - cl_type: lighthouse
+    cl_image: lighthouse:local
+    supernode: true # no supernode in Electra, this is for future proof
+    validator_count: 0
+  - cl_type: lighthouse
+    cl_image: lighthouse:local
+    supernode: false
+    validator_count: 0
+network_params:
+  seconds_per_slot: 6
+  electra_fork_epoch: 0
+  preset: "minimal"
+additional_services:
+  - tx_fuzz
+  - spamoor
+global_log_level: debug
diff --git a/scripts/tests/genesis-sync-config-fulu.yaml b/scripts/tests/genesis-sync-config-fulu.yaml
new file mode 100644
index 0000000000..ccdc09c0d3
--- /dev/null
+++ b/scripts/tests/genesis-sync-config-fulu.yaml
@@ -0,0 +1,22 @@
+# Kurtosis config file for testing sync on a local devnet.
+participants:
+  - cl_type: lighthouse
+    cl_image: lighthouse:local
+    count: 2
+  # nodes without validators, used for testing sync.
+  - cl_type: lighthouse
+    cl_image: lighthouse:local
+    supernode: true
+    validator_count: 0
+  - cl_type: lighthouse
+    cl_image: lighthouse:local
+    supernode: false
+    validator_count: 0
+network_params:
+  seconds_per_slot: 6
+  fulu_fork_epoch: 0
+  preset: "minimal"
+additional_services:
+  - tx_fuzz
+  - spamoor
+global_log_level: debug
diff --git a/scripts/tests/genesis-sync.sh b/scripts/tests/genesis-sync.sh
new file mode 100755
index 0000000000..39628c9e73
--- /dev/null
+++ b/scripts/tests/genesis-sync.sh
@@ -0,0 +1,151 @@
+#!/usr/bin/env bash
+#
+# Genesis sync test on a local network.
+#
+# Start a local testnet, shut down non-validator nodes for a period, then restart them
+# and monitor their sync progress from genesis to head.
+SCRIPT_DIR="$( cd -- "$( dirname -- "${BASH_SOURCE[0]}" )" &> /dev/null && pwd )"
+
+ENCLAVE_NAME=${1:-genesis-sync-testnet}
+CONFIG=${2:-$SCRIPT_DIR/genesis-sync-config-electra.yaml}
+FORK_TYPE=${3:-electra}  # electra or fulu
+OFFLINE_DURATION_SECS=${4:-120} # stopped duration  of non validating nodes
+
+# Test configuration
+# ------------------------------------------------------
+# Interval for polling the /lighthouse/syncing endpoint for sync status
+# Reduce the polling time so that some progress can be seen
+POLL_INTERVAL_SECS=0.5
+# Timeout for this test, if the nodes fail to sync, fail the test.
+TIMEOUT_MINS=5
+TIMEOUT_SECS=$((TIMEOUT_MINS * 60))
+# ------------------------------------------------------
+
+echo "Starting genesis sync test with:"
+echo "  Fork: $FORK_TYPE"
+echo "  Offline duration: ${OFFLINE_DURATION_SECS}s"
+
+# Polls a node's sync status
+poll_node() {
+  local node_type=$1
+  local url=${node_urls[$node_type]}
+
+  response=$(curl -s "${url}/lighthouse/syncing" 2>/dev/null)
+
+  if [ -z "$response" ] || [ "$response" = "null" ]; then
+    echo "${node_type} status: No response or null response"
+    return
+  fi
+  
+  # Print syncing status
+  sync_state=$(echo "$response" | jq -r 'if (.data | type) == "object" then "object" else "string" end' 2>/dev/null)
+
+  if [ "$sync_state" = "object" ]; then
+    status=$(echo "$response" | jq -r '.data | keys[0] // "Unknown"')
+    fields=$(echo "$response" | jq -r ".data.${status} | to_entries | map(\"\(.key): \(.value)\") | join(\", \")")
+    echo "${node_type} status: ${status}, ${fields}"
+  else
+    status=$(echo "$response" | jq -r '.data' 2>/dev/null)
+    echo "${node_type} status: ${status:-Unknown}"
+    
+    # The test is complete when the node is synced
+    if [ "$status" = "Synced" ]; then
+      mark_node_complete "$node_type"
+    fi
+  fi
+}
+
+# Marks a node as complete and record time
+mark_node_complete() {
+  local node_type=$1
+  if [ "${node_completed[$node_type]}" = false ]; then
+    node_completed[$node_type]=true
+    node_complete_time[$node_type]=$(date +%s)
+    echo "${node_type} completed sync in $((node_complete_time[$node_type] - sync_start_time)) seconds"
+  fi
+}
+
+exit_and_dump_logs() {
+    local exit_code=$1
+    echo "Shutting down..."
+    $SCRIPT_DIR/../local_testnet/stop_local_testnet.sh $ENCLAVE_NAME
+    echo "Test completed with exit code $exit_code."
+    exit $exit_code
+}
+
+# Start the nodes
+$SCRIPT_DIR/../local_testnet/start_local_testnet.sh -e $ENCLAVE_NAME -b false -n $CONFIG
+if [ $? -ne 0 ]; then
+  echo "Failed to start local testnet"
+  exit_and_dump_logs 1
+fi
+
+# Wait for 10s before stopping non-validating nodes
+sleep 10
+
+# These are non validating nodes
+supernode="cl-3-lighthouse-geth"
+fullnode="cl-4-lighthouse-geth"
+
+# Stop the non-validator nodes
+kurtosis service stop $ENCLAVE_NAME $supernode
+kurtosis service stop $ENCLAVE_NAME $fullnode
+
+echo "Non-validator nodes stopped. Waiting ${OFFLINE_DURATION_SECS} seconds..."
+
+# Display the time every 10s when the nodes are stopped
+remaining_time=$OFFLINE_DURATION_SECS
+while [ $remaining_time -gt 0 ]; do
+    sleep 10
+    remaining_time=$((remaining_time - 10))
+    echo "Nodes are stopped for $((OFFLINE_DURATION_SECS - remaining_time))s, ${remaining_time}s remains..."
+done
+
+echo "Resuming non-validator nodes..."
+
+# Resume the non validating nodes
+kurtosis service start $ENCLAVE_NAME $supernode
+kurtosis service start $ENCLAVE_NAME $fullnode
+
+# The time at which syncing starts after the node was stopped
+sync_start_time=$(date +%s)
+
+# Get beacon API URLs for non validating nodes for query
+supernode_url=$(kurtosis port print $ENCLAVE_NAME $supernode http)
+fullnode_url=$(kurtosis port print $ENCLAVE_NAME $fullnode http)
+
+# Initialize statuses
+declare -A node_completed
+declare -A node_complete_time
+declare -A node_urls
+
+node_urls["supernode"]="$supernode_url"
+node_urls["fullnode"]="$fullnode_url"
+node_completed["supernode"]=false
+node_completed["fullnode"]=false
+
+echo "Polling sync status until nodes are synced or timeout of ${TIMEOUT_MINS} mins"
+
+while [ "${node_completed[supernode]}" = false ] || [ "${node_completed[fullnode]}" = false ]; do
+  current_time=$(date +%s)
+  elapsed=$((current_time - sync_start_time))
+
+  if [ "$elapsed" -ge "$TIMEOUT_SECS" ]; then
+    echo "ERROR: Nodes timed out syncing after ${TIMEOUT_MINS} minutes. Exiting."
+    exit_and_dump_logs 1
+  fi
+
+  # Poll each node that hasn't completed yet
+  for node in "supernode" "fullnode"; do
+    if [ "${node_completed[$node]}" = false ]; then
+      poll_node "$node"
+    fi
+  done
+
+  sleep $POLL_INTERVAL_SECS
+done
+
+echo "Genesis sync test complete! Both supernode and fullnode have synced successfully."
+echo "Supernode time: $((node_complete_time[supernode] - sync_start_time)) seconds"
+echo "Fullnode time: $((node_complete_time[fullnode] - sync_start_time)) seconds"
+exit_and_dump_logs 0
\ No newline at end of file