diff -up src/sage/databases/cremona.py.orig src/sage/databases/cremona.py
--- src/sage/databases/cremona.py.orig	2020-10-24 11:37:59.000000000 -0600
+++ src/sage/databases/cremona.py	2020-10-30 14:02:27.778960819 -0600
@@ -854,7 +854,8 @@ class MiniCremonaDatabase(SQLDatabase):
                 message = "There is no elliptic curve with label " \
                     + label + " in the default database; try installing " \
                     + "the optional package database_cremona_ellcurve which " \
-                    + "contains the complete Cremona database"
+                    + "contains the complete Cremona database: " \
+                    + "sudo dnf install sagemath-data-elliptic_curves_large"
             raise ValueError(message)
         ainvs = eval(c[0])
         data = {'cremona_label': label,
@@ -1659,6 +1660,7 @@ class LargeCremonaDatabase(MiniCremonaDa
             con.executemany("UPDATE t_curve SET gens=? WHERE curve=?", \
                 curve_data)
             print("Committing...")
+            self.commit()
             if largest_conductor and int(v[0]) > largest_conductor: break