diff --git a/installer/data/mysql/atomicupdate/bug_31086_do_not_allow_null_branchcode_in_reserves.pl b/installer/data/mysql/atomicupdate/bug_31086_do_not_allow_null_branchcode_in_reserves.pl
index 1c817a2f26..ea2c1a6eb4 100755
--- a/installer/data/mysql/atomicupdate/bug_31086_do_not_allow_null_branchcode_in_reserves.pl
+++ b/installer/data/mysql/atomicupdate/bug_31086_do_not_allow_null_branchcode_in_reserves.pl
@@ -6,10 +6,18 @@ return {
     up => sub {
         my ($args) = @_;
         my ($dbh, $out) = @$args{qw(dbh out)};
+
+        # Ensure we have no NULL's in the branchcode field
+        $dbh->do(q{
+            UPDATE reserves SET branchcode = ( SELECT branchcode FROM branches LIMIT 1) WHERE branchode IS NULL;
+        });
+
+        # Set the NOT NULL configuration
         $dbh->do(q{
             ALTER TABLE reserves
             MODIFY COLUMN `branchcode` varchar(10) COLLATE utf8mb4_unicode_ci NOT NULL COMMENT 'foreign key from the branches table defining which branch the patron wishes to pick this hold up at'
         });
+
         # Print useful stuff here
         say $out "Removed NULL option from branchcode for reserves";
     },