diff --git a/db/queries/queries.sql b/db/queries/queries.sql
index 60196e3..3744ed0 100644
--- a/db/queries/queries.sql
+++ b/db/queries/queries.sql
@@ -236,6 +236,13 @@ ON CONFLICT (channel_hash, key_fingerprint) DO UPDATE SET
   message_count = CASE WHEN $6 THEN channels.message_count + 1 ELSE channels.message_count END
 RETURNING *;
 
+-- name: UpsertChannelHashOnly :one
+INSERT INTO channels (channel_hash, last_seen)
+VALUES ($1, NOW())
+ON CONFLICT (channel_hash) WHERE key_fingerprint IS NULL DO UPDATE SET
+  last_seen = NOW()
+RETURNING id;
+
 -- name: SetChannelKeyKnown :exec
 UPDATE channels SET key_known = TRUE
 WHERE channel_hash = $1 AND key_fingerprint = $2;
diff --git a/db/sqlc/queries.sql.go b/db/sqlc/queries.sql.go
index 9bae5ac..fa84665 100644
--- a/db/sqlc/queries.sql.go
+++ b/db/sqlc/queries.sql.go
@@ -1319,6 +1319,21 @@ func (q *Queries) UpsertChannel(ctx context.Context, arg UpsertChannelParams) (C
 	return i, err
 }
 
+const upsertChannelHashOnly = `-- name: UpsertChannelHashOnly :one
+INSERT INTO channels (channel_hash, last_seen)
+VALUES ($1, NOW())
+ON CONFLICT (channel_hash) WHERE key_fingerprint IS NULL DO UPDATE SET
+  last_seen = NOW()
+RETURNING id
+`
+
+func (q *Queries) UpsertChannelHashOnly(ctx context.Context, channelHash []byte) (int32, error) {
+	row := q.db.QueryRow(ctx, upsertChannelHashOnly, channelHash)
+	var id int32
+	err := row.Scan(&id)
+	return id, err
+}
+
 const upsertIATA = `-- name: UpsertIATA :exec
 
 INSERT INTO iata_codes (iata)
diff --git a/db/store.go b/db/store.go
index d69f2cc..1a65e7c 100644
--- a/db/store.go
+++ b/db/store.go
@@ -233,6 +233,18 @@ func (s *Store) UpsertChannel(ctx context.Context, channelHash []byte, keyFinger
 	return int(row.ID), nil
 }
 
+// UpsertChannelHashOnly upserts a hash-only channel row for cases where the
+// channel key is unknown. Uses the partial unique index to ensure only one
+// hash-only row exists per channel hash. The return value is the channel ID
+// but can be safely ignored since unknown-key channels have no messages.
+func (s *Store) UpsertChannelHashOnly(ctx context.Context, channelHash []byte) (int, error) {
+	rowID, err := s.q.UpsertChannelHashOnly(ctx, channelHash)
+	if err != nil {
+		return 0, err
+	}
+	return int(rowID), nil
+}
+
 // ListIATAs returns all known IATA codes with display name and coordinates.
 // IATAs are auto-created on first packet arrival from that location.
 func (s *Store) ListIATAs(ctx context.Context) ([]api.IATA, error) {
diff --git a/internal/ingest/ingest.go b/internal/ingest/ingest.go
index e8a80ec..1997d9c 100644
--- a/internal/ingest/ingest.go
+++ b/internal/ingest/ingest.go
@@ -100,6 +100,12 @@ type DB interface {
 	// UpsertChannel upserts a channel row by (hash, keyFingerprint) and returns its integer ID.
 	// Pass nil keyFingerprint to record a hash-only row when the key is unknown.
 	UpsertChannel(ctx context.Context, channelHash []byte, keyFingerprint []byte, name string, hashtag string) (int, error)
+
+	// UpsertChannelHashOnly upserts a hash-only channel row for cases where the
+	// channel key is unknown. Uses the partial unique index to ensure only one
+	// hash-only row exists per channel hash. The return value is the channel ID
+	// but can be safely ignored since unknown-key channels have no messages.
+	UpsertChannelHashOnly(ctx context.Context, channelHash []byte) (int, error)
 }
 
 // UpsertPacketParams mirrors the columns written on packets upsert.
@@ -671,7 +677,7 @@ func (w *Worker) handlePayloadTypeSideEffects(ctx context.Context, packet *meshc
 		channelHashBytes := []byte{grpTxt.ChannelHash}
 
 		// Always upsert a hash-only row so unknown channels are recorded.
-		_, _ = w.db.UpsertChannel(ctx, channelHashBytes, nil, "", "")
+		_, _ = w.db.UpsertChannelHashOnly(ctx, channelHashBytes)
 
 		// Try each known key entry for this hash.
 		entries := w.keys.GetKey(channelHashBytes)