diff --git a/tools/fleet/base-unit-gate.sh b/tools/fleet/base-unit-gate.sh
index 33d3445d5..64dca329f 100755
--- a/tools/fleet/base-unit-gate.sh
+++ b/tools/fleet/base-unit-gate.sh
@@ -21,6 +21,9 @@
 # does 0.147 MH/s on 32 threads, so a block takes 10 to 30 minutes on CPU; the ten-minute, hundreds-of-blocks form of
 # this gate needs a GPU wave box (the fleet lane's); on the box alone run it for an hour with MIN_BLOCKS=3.
 #
+# A fresh chain is never "synced" by the mining rule (its sink is the two-day-old genesis), so both nodes run with
+# --enable-unsynced-mining, as a devnet's first node does; without it every found block is Reject(IsInIBD) (seen 00:2x UK).
+#
 # Known-failed case: run with GATE_EXPECT_DECIMALS=8 against the same nodes and check 3 and 5 fail (the schedule at 8
 # does not match an 18-decimal chain). The self-test target below does that on the recorded output.
 set -euo pipefail
@@ -40,13 +43,13 @@ rm -rf "$ROOT"; mkdir -p "$ROOT/a" "$ROOT/b"
 [ -x "$BIN/igneumd" ] && [ -x "$BIN/igneum-miner" ] || { echo "FAIL: binaries missing in $BIN"; exit 2; }
 
 say "starting node A (testnet params, 18 decimals)"
-"$BIN/igneumd" --testnet --netsuffix=1 --appdir="$ROOT/a" --listen=127.0.0.1:$A_P2P --rpclisten=127.0.0.1:$A_RPC --evm-rpclisten=127.0.0.1:$A_EVM --outpeers=1 --loglevel=info > "$ROOT/a.log" 2>&1 &
+"$BIN/igneumd" --testnet --netsuffix=1 --enable-unsynced-mining --appdir="$ROOT/a" --listen=127.0.0.1:$A_P2P --rpclisten=127.0.0.1:$A_RPC --evm-rpclisten=127.0.0.1:$A_EVM --outpeers=1 --loglevel=info > "$ROOT/a.log" 2>&1 &
 echo $! > "$ROOT/a.pid"
 sleep 3
 grep -m1 "Base unit" "$ROOT/a.log" || true
 if grep -q -E "refusing to start|panicked" "$ROOT/a.log"; then die "node A did not start: $(grep -m1 -E 'refusing|panicked' "$ROOT/a.log")"; exit 1; fi
 say "starting node B, connected to A"
-"$BIN/igneumd" --testnet --netsuffix=1 --appdir="$ROOT/b" --listen=127.0.0.1:$B_P2P --rpclisten=127.0.0.1:$B_RPC --evm-rpclisten=127.0.0.1:$B_EVM --connect=127.0.0.1:$A_P2P --loglevel=info > "$ROOT/b.log" 2>&1 &
+"$BIN/igneumd" --testnet --netsuffix=1 --enable-unsynced-mining --appdir="$ROOT/b" --listen=127.0.0.1:$B_P2P --rpclisten=127.0.0.1:$B_RPC --evm-rpclisten=127.0.0.1:$B_EVM --connect=127.0.0.1:$A_P2P --loglevel=info > "$ROOT/b.log" 2>&1 &
 echo $! > "$ROOT/b.pid"
 for i in $(seq 1 60); do
   if curl -s -m 2 -X POST -H 'content-type: application/json' --data '{"jsonrpc":"2.0","id":1,"method":"eth_blockNumber","params":[]}' http://127.0.0.1:$A_EVM | grep -q result \