diff --git a/src/bsc_hack.c b/src/bsc_hack.c
index 145b552..5d89124 100644
--- a/src/bsc_hack.c
+++ b/src/bsc_hack.c
@@ -545,8 +545,8 @@
 static_assert(sizeof(si2) == sizeof(struct gsm48_system_information_type_2), type2)
 static_assert(sizeof(si3) == sizeof(struct gsm48_system_information_type_3), type3)
 static_assert(sizeof(si4) >= sizeof(struct gsm48_system_information_type_4), type4)
-static_assert(sizeof(si5) == sizeof(struct gsm48_system_information_type_5)-1, type5)
-static_assert(sizeof(si6) >= sizeof(struct gsm48_system_information_type_6)-1, type6)
+static_assert(sizeof(si5) == sizeof(struct gsm48_system_information_type_5), type5)
+static_assert(sizeof(si6) >= sizeof(struct gsm48_system_information_type_6), type6)
 
 /* set all system information types */
 static int set_system_infos(struct gsm_bts *bts)