--- ./lib/backend/bdb_ro.c.orig	2020-01-17 15:48:50.622349363 +0000
+++ ./lib/backend/bdb_ro.c	2020-01-17 15:49:20.514287856 +0000
@@ -795,6 +795,7 @@ static unsigned int bdbro_pkgdbKey(dbiIn
 struct rpmdbOps_s bdbro_dbops = {
     .name       = "bdb_ro",
     .path       = "Packages",
+    .readonly   = 1,
 
     .open       = bdbro_Open,
     .close      = bdbro_Close,
--- ./lib/backend/dbi.c.orig	2020-01-17 15:48:50.622349363 +0000
+++ ./lib/backend/dbi.c	2020-01-17 15:49:20.514287856 +0000
@@ -105,11 +105,20 @@ dbDetectBackend(rpmdb rdb)
     }
 
     rdb->db_descr = rdb->db_ops->name;
+    rdb->db_ops_config = ops_config;
 
     if (db_backend)
 	free(db_backend);
 }
 
+int dbiNeedConversion(rpmdb rdb)
+{
+    if (!rdb->db_ops)
+	dbDetectBackend(rdb);
+    return rdb->db_ops->readonly && rdb->db_ops_config
+	&& rdb->db_ops_config->path && !rdb->db_ops_config->readonly;
+}
+
 const char * dbiName(dbiIndex dbi)
 {
     return dbi->dbi_file;
--- ./lib/backend/dbi.h.orig	2020-01-17 15:48:50.622349363 +0000
+++ ./lib/backend/dbi.h	2020-01-17 15:49:49.886227415 +0000
@@ -10,6 +10,7 @@ enum rpmdbFlags {
     RPMDB_FLAG_JUSTCHECK	= (1 << 0),
     RPMDB_FLAG_REBUILD		= (1 << 1),
     RPMDB_FLAG_VERIFYONLY	= (1 << 2),
+    RPMDB_FLAG_CONVERT		= (1 << 3),
 };
 
 typedef enum dbCtrlOp_e {
@@ -62,6 +63,7 @@ struct rpmdb_s {
     int		db_buildindex;	/*!< Index rebuild indicator */
 
     const struct rpmdbOps_s * db_ops;	/*!< backend ops */
+    const struct rpmdbOps_s * db_ops_config;	/*!< configured backend ops */
 
     /* dbenv and related parameters */
     void * db_dbenv;		/*!< Backend private handle */
@@ -201,6 +203,14 @@ RPM_GNUC_INTERNAL
 const char * dbiName(dbiIndex dbi);
 
 /** \ingroup dbi
+ * Check if the database needs to be converted to a different format
+ * @param db           rpm database
+ * @return             boolean
+ */
+RPM_GNUC_INTERNAL
+int dbiNeedConversion(rpmdb rdb);
+
+/** \ingroup dbi
  * Open a database cursor.
  * @param dbi		index database handle
  * @param flags		DBC_WRITE if writing, or 0 (DBC_READ) for reading
@@ -246,6 +256,7 @@ const void * idxdbKey(dbiIndex dbi, dbiC
 struct rpmdbOps_s {
     const char *name; /* backend name */
     const char *path; /* main database name */
+    int readonly;     /* cannot modify database */
 
     int (*open)(rpmdb rdb, rpmDbiTagVal rpmtag, dbiIndex * dbip, int flags);
     int (*close)(dbiIndex dbi, unsigned int flags);
--- ./lib/rpmdb.c.orig	2020-01-17 15:48:50.622349363 +0000
+++ ./lib/rpmdb.c	2020-01-17 15:53:52.241669094 +0000
@@ -513,8 +513,16 @@ static int openDatabase(const char * pre
 	    rpmsqActivate(1);
 	}
 
+	/* Convert the database if needed */
+	if (!db->db_pkgs && !justCheck && (mode & O_ACCMODE) == O_RDWR && dbiNeedConversion(db)) {
+	    rpmlog(RPMLOG_WARNING, _("Converting database from %s to %s format\n"), db->db_ops->name, db->db_ops_config->name);
+	    rc = rpmdbRebuild(prefix, NULL, NULL, RPMDB_FLAG_CONVERT);
+	    db->db_ops = NULL;		/* force re-detection of backend */
+	}
+
 	/* Just the primary Packages database opened here */
-	rc = pkgdbOpen(db, db->db_flags, NULL);
+	if (!rc)
+	    rc = pkgdbOpen(db, db->db_flags, NULL);
 	if (!db->db_descr)
 	    db->db_descr = "unknown db";
     }
@@ -2316,6 +2324,15 @@ int rpmdbAdd(rpmdb db, Header h)
     if (db == NULL)
 	return 0;
 
+    if ((db->db_flags & RPMDB_FLAG_CONVERT) != 0) {
+	/* keep old instance numbers when converting */
+	hdrNum = headerGetInstance(h);
+	if (hdrNum == 0) {
+	    ret = -1;
+	    goto exit;
+	}
+    }
+
     hdrBlob = headerExport(h, &hdrLen);
     if (hdrBlob == NULL || hdrLen == 0) {
 	ret = -1;
@@ -2331,7 +2348,8 @@ int rpmdbAdd(rpmdb db, Header h)
 
     /* Add header to primary index */
     dbc = dbiCursorInit(dbi, DBC_WRITE);
-    ret = pkgdbNew(dbi, dbc, &hdrNum);
+    if ((db->db_flags & RPMDB_FLAG_CONVERT) == 0)
+	ret = pkgdbNew(dbi, dbc, &hdrNum);
     if (ret == 0)
 	ret = pkgdbPut(dbi, dbc, hdrNum, hdrBlob, hdrLen);
     dbiCursorFree(dbi, dbc);
@@ -2491,7 +2509,8 @@ static int rpmdbSetPermissions(char * sr
 }
 
 int rpmdbRebuild(const char * prefix, rpmts ts,
-		rpmRC (*hdrchk) (rpmts ts, const void *uh, size_t uc, char ** msg))
+		rpmRC (*hdrchk) (rpmts ts, const void *uh, size_t uc, char ** msg),
+		int newdbflags)
 {
     rpmdb olddb;
     char * dbpath = NULL;
@@ -2536,7 +2555,7 @@ int rpmdbRebuild(const char * prefix, rp
 	goto exit;
     }
     if (openDatabase(prefix, newdbpath, &newdb,
-		     (O_RDWR | O_CREAT), 0644, RPMDB_FLAG_REBUILD)) {
+		     (O_RDWR | O_CREAT), 0644, RPMDB_FLAG_REBUILD | newdbflags)) {
 	rc = 1;
 	goto exit;
     }
--- ./lib/rpmdb_internal.h.orig	2020-01-17 15:51:16.134030103 +0000
+++ ./lib/rpmdb_internal.h	2020-01-17 15:50:27.050144956 +0000
@@ -63,11 +63,13 @@ int rpmdbClose (rpmdb db);
  * @param prefix	path to top of install tree
  * @param ts		transaction set (or NULL)
  * @param (*hdrchk)	headerCheck() vector (or NULL)
+ * @param newdbflags	extra flags for the new database
  * @return		0 on success
  */
 RPM_GNUC_INTERNAL
 int rpmdbRebuild(const char * prefix, rpmts ts,
-		rpmRC (*hdrchk) (rpmts ts, const void *uh, size_t uc, char ** msg));
+		rpmRC (*hdrchk) (rpmts ts, const void *uh, size_t uc, char ** msg),
+		int newdbflags);
 
 /** \ingroup rpmdb
  * Verify database components.
--- ./lib/rpmts.c.orig	2020-01-17 15:51:37.813979967 +0000
+++ ./lib/rpmts.c	2020-01-17 15:51:48.925954269 +0000
@@ -143,9 +143,9 @@ int rpmtsRebuildDB(rpmts ts)
     txn = rpmtxnBegin(ts, RPMTXN_WRITE);
     if (txn) {
 	if (!(ts->vsflags & RPMVSF_NOHDRCHK))
-	    rc = rpmdbRebuild(ts->rootDir, ts, headerCheck);
+	    rc = rpmdbRebuild(ts->rootDir, ts, headerCheck, 0);
 	else
-	    rc = rpmdbRebuild(ts->rootDir, NULL, NULL);
+	    rc = rpmdbRebuild(ts->rootDir, NULL, NULL, 0);
 	rpmtxnEnd(txn);
     }
     return rc;