diff --git a/README.md b/README.md
index d4750f5..699d23c 100644
--- a/README.md
+++ b/README.md
@@ -27,6 +27,10 @@ Register the serv repo as a core library
 
 `cd $SERV/workspace && fusesoc library add serv ../serv`
 
+Check that the CPU passes the linter
+
+`cd $SERV/workspace && fusesoc run --target=lint serv`
+
 Running test software
 ---------------------
 
diff --git a/rtl/serv_params.vh b/rtl/serv_params.vh
index 5f14c71..c218de7 100644
--- a/rtl/serv_params.vh
+++ b/rtl/serv_params.vh
@@ -1,8 +1,8 @@
 localparam [1:0]
-  RD_SOURCE_CTRL = 3'd0,
-  RD_SOURCE_ALU  = 3'd1,
-  RD_SOURCE_MEM  = 3'd2,
-  RD_SOURCE_CSR  = 3'd3;
+  RD_SOURCE_CTRL = 2'd0,
+  RD_SOURCE_ALU  = 2'd1,
+  RD_SOURCE_MEM  = 2'd2,
+  RD_SOURCE_CSR  = 2'd3;
 
 localparam [0:0]
   OFFSET_SOURCE_IMM = 1'd0,