diff --git a/model/riscv_sys_regs.sail b/model/riscv_sys_regs.sail
index 9c9969994..4af215c0c 100644
--- a/model/riscv_sys_regs.sail
+++ b/model/riscv_sys_regs.sail
@@ -188,10 +188,10 @@ function haveNExt()    -> bool = misa.N() == 0b1
 /* see below for F and D (and Z*inx counterparts) extension tests */
 
 /* BitManip extension support. */
-function haveZba()  -> bool = haveBExt()
-function haveZbb()  -> bool = haveBExt()
+function haveZba()  -> bool = true
+function haveZbb()  -> bool = true
 function haveZbc()  -> bool = true
-function haveZbs()  -> bool = haveBExt()
+function haveZbs()  -> bool = true
 
 /* Zfa (additional FP) extension */
 function haveZfa()  -> bool = true