diff --git a/mysql/migration/2.1.0-2.2.0.sql b/mysql/migration/2.1.0-2.2.0.sql
index ddb61d4edaa..18f571feac5 100644
--- a/mysql/migration/2.1.0-2.2.0.sql
+++ b/mysql/migration/2.1.0-2.2.0.sql
@@ -823,4 +823,4 @@ alter table llx_boxes modify box_order varchar(3) NOT NULL;
 
 
 alter table llx_bordereau_cheque modify number integer;
-ALTER TABLE llx_facturedet ADD COLUMN special_code tinyint unsigned default 0;
\ No newline at end of file
+ALTER TABLE llx_facturedet ADD COLUMN special_code tinyint(4) default 0;
\ No newline at end of file
diff --git a/mysql/tables/llx_facturedet.sql b/mysql/tables/llx_facturedet.sql
index bb6430353b7..3fdd64a224a 100644
--- a/mysql/tables/llx_facturedet.sql
+++ b/mysql/tables/llx_facturedet.sql
@@ -42,5 +42,5 @@ create table llx_facturedet
   fk_code_ventilation integer DEFAULT 0 NOT NULL,
   fk_export_compta    integer DEFAULT 0 NOT NULL,
   rang                integer DEFAULT 0,         -- ordre d'affichage
-  special_code    tinyint UNSIGNED DEFAULT 0, -- code pour les lignes speciales (livraison=1, ecotaxe=2)
+  special_code    tinyint(4) DEFAULT 0   -- code pour les lignes speciales (livraison=1, ecotaxe=2)
 )type=innodb;