diff --git a/core/csr_regfile.sv b/core/csr_regfile.sv
index a01ccd808d..8232e312b8 100644
--- a/core/csr_regfile.sv
+++ b/core/csr_regfile.sv
@@ -280,7 +280,7 @@ module csr_regfile
   logic [3:0] index;
 
   localparam logic [CVA6Cfg.XLEN-1:0] IsaCode = (CVA6Cfg.XLEN'(CVA6Cfg.RVA) <<  0)                // A - Atomic Instructions extension
-  | (CVA6Cfg.XLEN'(CVA6Cfg.RVB) << 1)  // C - Bitmanip extension
+  | (CVA6Cfg.XLEN'(CVA6Cfg.RVB) << 1)  // B - Bitmanip extension
   | (CVA6Cfg.XLEN'(CVA6Cfg.RVC) << 2)  // C - Compressed extension
   | (CVA6Cfg.XLEN'(CVA6Cfg.RVD) << 3)  // D - Double precision floating-point extension
   | (CVA6Cfg.XLEN'(CVA6Cfg.RVF) << 5)  // F - Single precision floating-point extension