diff --git a/pkg/atproto/sweep.go b/pkg/atproto/sweep.go
index 089291f7f..a5faea716 100644
--- a/pkg/atproto/sweep.go
+++ b/pkg/atproto/sweep.go
@@ -452,6 +452,11 @@ func (atsync *ATProtoSynchronizer) sweepBootDelay(ctx context.Context) time.Dura
 	delay := config.DefaultSweepBootDelay
 	if atsync.CLI != nil {
 		delay = atsync.CLI.SweepBootDelay
+		if atsync.CLI.NoFirehose {
+			// No firehose means no replay to heal the restart's gap: the boot
+			// sweep is this node's only reconciliation, so it does not wait.
+			return 0
+		}
 	}
 	if delay <= 0 {
 		return 0
diff --git a/pkg/atproto/sweep_test.go b/pkg/atproto/sweep_test.go
index ebedfb0a9..77dd900ba 100644
--- a/pkg/atproto/sweep_test.go
+++ b/pkg/atproto/sweep_test.go
@@ -816,6 +816,12 @@ func TestSweepBootDelay(t *testing.T) {
 	require.NoError(t, mod.UpdateRepo(&model.Repo{DID: "did:plc:warmbootdelaytest", Version: "rev"}))
 	require.Equal(t, 42*time.Minute, atsync.sweepBootDelay(ctx), "a warm index waits")
 
+	atsync.CLI.SweepBootDelay = 42 * time.Minute
+	atsync.CLI.NoFirehose = true
+	require.Equal(t, time.Duration(0), atsync.sweepBootDelay(ctx),
+		"without a firehose there is no replay to heal the gap; the sweep is all this node has")
+	atsync.CLI.NoFirehose = false
+
 	atsync.CLI.SweepBootDelay = 0
 	require.Equal(t, time.Duration(0), atsync.sweepBootDelay(ctx), "0 disables the hold")
 }
diff --git a/pkg/config/config.go b/pkg/config/config.go
index c8ba77470..e63134ea4 100644
--- a/pkg/config/config.go
+++ b/pkg/config/config.go
@@ -882,7 +882,7 @@ func (cli *CLI) NewCommand(name string) *urfavecli.Command {
 			},
 			&urfavecli.DurationFlag{
 				Name:        "sweep-boot-delay",
-				Usage:       "how long a node with a warm index waits after boot before its first sweep, so the sweep's reindexing does not compound the busiest minutes of a restart. A fresh (empty) index always sweeps immediately, and 0 sweeps immediately in every case",
+				Usage:       "how long a node with a warm index waits after boot before its first sweep, so the sweep's reindexing does not compound the busiest minutes of a restart. A fresh (empty) index always sweeps immediately, as does a --no-firehose node (no replay heals its gap), and 0 sweeps immediately in every case",
 				Value:       DefaultSweepBootDelay,
 				Destination: &cli.SweepBootDelay,
 				Sources:     urfavecli.EnvVars("SP_SWEEP_BOOT_DELAY"),