diff --git a/firmware/storage.c b/firmware/storage.c
index 248e19bb10..436d4460e2 100644
--- a/firmware/storage.c
+++ b/firmware/storage.c
@@ -215,6 +215,7 @@ bool storage_from_flash(void)
 		u2fword >>= 1;
 	}
 	// force recomputing u2f root for storage version < 9.
+	// this is done by re-setting the mnemonic, which triggers the computation
 	if (version < 9) {
 		storageUpdate.has_mnemonic = storageRom->has_mnemonic;
 		strlcpy(storageUpdate.mnemonic, storageRom->mnemonic, sizeof(storageUpdate.mnemonic));
diff --git a/vendor/trezor-common b/vendor/trezor-common
index 8e96b42260..8019bd2730 160000
--- a/vendor/trezor-common
+++ b/vendor/trezor-common
@@ -1 +1 @@
-Subproject commit 8e96b42260b84e1e0f0b00a5e528d19258c57031
+Subproject commit 8019bd2730ce7e4b2351e2441dbea38191ed14d9