diff --git a/core/state/database_hasher_binary.go b/core/state/database_hasher_binary.go
index 355f56b25d..0e843d31ff 100644
--- a/core/state/database_hasher_binary.go
+++ b/core/state/database_hasher_binary.go
@@ -129,10 +129,11 @@ func (tr *warpBinTrie) copy() *warpBinTrie {
 //
 // binaryHasher also implements LeafProducer: alongside every trie mutation
 // it records the corresponding (stem, offset, value) write into an
-// internal buffer. The caller (StateDB.Commit in a later commit) drains
-// this buffer once per block and hands the writes to the pathdb flat-state
-// layer via the stateUpdate, keeping the bintrie trie and its flat-state
-// mirror consistent without recomputing the bintrie key derivation twice.
+// internal buffer. StateDB.commit() drains this buffer once per block
+// via LeafProducer.DrainStemWrites and hands the writes to the pathdb
+// flat-state layer via stateUpdate.encodeBinary, keeping the bintrie
+// trie and its flat-state mirror consistent without recomputing the
+// bintrie key derivation twice.
 type binaryHasher struct {
 	db   *triedb.Database
 	root common.Hash
diff --git a/triedb/pathdb/flat_codec_bintrie.go b/triedb/pathdb/flat_codec_bintrie.go
index 28ea2ba253..a55d87b2b1 100644
--- a/triedb/pathdb/flat_codec_bintrie.go
+++ b/triedb/pathdb/flat_codec_bintrie.go
@@ -47,15 +47,13 @@ import (
 // reads the stem from the store (not from the in-flight batch), so a
 // second write at the same stem would re-read the pre-flush state and
 // clobber the first write. The codec's public surface area is designed
-// around this assumption; Commit 8 of the bintrie flat-state plan
-// restructures writeStates to pre-aggregate per-stem writes so callers
-// do not have to handle this manually.
+// around this assumption; the Flush method pre-aggregates per-stem
+// writes so callers do not have to handle this manually.
 //
-// This codec is NOT wired into pathdb.Database.New yet — that happens in a
-// later commit once the leaf-production hook in binaryHasher and the
-// stateUpdate wiring are in place. Until then, all call sites still
-// dispatch through merkleFlatCodec and bintrie mode continues to use the
-// (soon to be replaced) keccak-shaped flat-state layout.
+// This codec is wired into pathdb.Database.New when isVerkle is true
+// (see database.go). The leaf-production hook in binaryHasher emits
+// per-offset writes via DrainStemWrites, which encodeBinary routes
+// into the per-offset accountData map consumed by Flush.
 type bintrieFlatCodec struct {
 	// db is the underlying key-value store used by applyWrites to read
 	// the current stem blob before merging in new (offset, value) pairs.
@@ -357,9 +355,10 @@ func (c *bintrieFlatCodec) AccountPrefix() []byte {
 
 // StoragePrefix returns the same prefix as AccountPrefix because bintrie
 // flat-state entries are stored in a single namespace (stems contain
-// both account and storage data). The generator in a later commit uses
-// a single iterator over this prefix rather than the two-tier
-// account-then-storage walk used by the merkle generator.
+// both account and storage data). The bintrie generator
+// (generate_bintrie.go) uses a single iterator over this prefix
+// rather than the two-tier account-then-storage walk used by the
+// merkle generator.
 func (c *bintrieFlatCodec) StoragePrefix() []byte {
 	return rawdb.BinTrieStemPrefix
 }
diff --git a/triedb/pathdb/journal.go b/triedb/pathdb/journal.go
index 7a91419669..d586553d5b 100644
--- a/triedb/pathdb/journal.go
+++ b/triedb/pathdb/journal.go
@@ -50,10 +50,10 @@ var (
 // - Version 1: storage.Incomplete field is removed
 // - Version 2: add post-modification state values
 // - Version 3: a flag has been added to indicate whether the storage slot key is the raw key or a hash
-// - Version 4: reserved for bintrie flat-state (per-stem layout). Bumping now
-//              discards any v3 journals belonging to a bintrie database so
-//              that the new layout can be introduced cleanly in follow-up
-//              commits without a migration path.
+// - Version 4: bintrie flat-state per-stem layout. The journalGenerator
+//              struct gains an IsBintrie flag (rlp:"optional", defaults to
+//              false) so the loader can discard journals from a mismatched
+//              scheme and trigger a full flat-state regeneration.
 const journalVersion uint64 = 4
 
 // loadJournal tries to parse the layer journal from the disk.