diff --git a/gateware/cal/cal.sv b/gateware/cal/cal.sv
index 1e327bf..44ea2b8 100644
--- a/gateware/cal/cal.sv
+++ b/gateware/cal/cal.sv
@@ -18,7 +18,11 @@
 
 module cal #(
     parameter W = 16, // sample width
-    parameter CAL_MEM_FILE = "cal/cal_mem.hex"
+`ifdef HW_R33
+    parameter CAL_MEM_FILE = "cal/cal_mem_default_r33.hex"
+`else
+    parameter CAL_MEM_FILE = "cal/cal_mem_default_r31.hex"
+`endif
 )(
     input rst,
     input clk_256fs,
diff --git a/gateware/eurorack_pmod.sv b/gateware/eurorack_pmod.sv
index fc1ab0a..8cdf403 100644
--- a/gateware/eurorack_pmod.sv
+++ b/gateware/eurorack_pmod.sv
@@ -9,7 +9,6 @@
 
 module eurorack_pmod #(
     parameter W = 16, // sample width, bits
-    parameter CAL_MEM_FILE = "cal/cal_mem.hex",
     parameter CODEC_CFG_FILE  = "drivers/ak4619-cfg.hex",
     parameter LED_CFG_FILE  = "drivers/pca9635-cfg.hex"
 )(
@@ -73,8 +72,7 @@ logic signed [W-1:0] sample_dac3;
 // Compensates for DC bias in CODEC, gain differences, resistor
 // tolerances and so on.
 cal #(
-    .W(W),
-    .CAL_MEM_FILE(CAL_MEM_FILE)
+    .W(W)
 ) cal_instance (
     .rst(rst),
     .clk_256fs (clk_256fs),
diff --git a/gateware/mk/ecp5.mk b/gateware/mk/ecp5.mk
index 98b8389..78749ac 100644
--- a/gateware/mk/ecp5.mk
+++ b/gateware/mk/ecp5.mk
@@ -1,4 +1,4 @@
-DEFINES = "$(ADD_DEFINES) -DECP5 -DHW_REV=$(HW_REV)"
+DEFINES = "$(ADD_DEFINES) -DECP5 -D$(HW_REV)"
 
 all: $(BUILD)/$(PROJ).bin
 
diff --git a/gateware/mk/ice40.mk b/gateware/mk/ice40.mk
index 571e708..8687941 100644
--- a/gateware/mk/ice40.mk
+++ b/gateware/mk/ice40.mk
@@ -1,4 +1,4 @@
-DEFINES = "$(ADD_DEFINES) -DICE40 -DHW_REV=$(HW_REV)"
+DEFINES = "$(ADD_DEFINES) -DICE40 -D$(HW_REV)"
 
 all: $(BUILD)/$(PROJ).bin
 
diff --git a/gateware/sim/cal/cal/cal_mem.hex b/gateware/sim/cal/cal/cal_mem_default_r31.hex
similarity index 100%
rename from gateware/sim/cal/cal/cal_mem.hex
rename to gateware/sim/cal/cal/cal_mem_default_r31.hex
diff --git a/gateware/sim/cal/tb_cal.py b/gateware/sim/cal/tb_cal.py
index d9e2bf2..0efccfb 100644
--- a/gateware/sim/cal/tb_cal.py
+++ b/gateware/sim/cal/tb_cal.py
@@ -32,7 +32,7 @@ async def test_cal_00(dut):
     ]
 
     cal_mem = []
-    with open("cal/cal_mem.hex", "r") as f_cal_mem:
+    with open("cal/cal_mem_default_r31.hex", "r") as f_cal_mem:
         for line in f_cal_mem.readlines():
             if '//' in line:
                 continue
diff --git a/gateware/top.sv b/gateware/top.sv
index a54f414..56a6e1e 100644
--- a/gateware/top.sv
+++ b/gateware/top.sv
@@ -130,12 +130,7 @@ assign i2c_sda_i = PMOD_I2C_SDA;
 `endif
 
 eurorack_pmod #(
-    .W(W),
-`ifdef HW_R33
-    .CAL_MEM_FILE("cal/cal_mem_default_r33.hex")
-`else
-    .CAL_MEM_FILE("cal/cal_mem_default_r31.hex")
-`endif
+    .W(W)
 ) eurorack_pmod1 (
     .clk_256fs(clk_256fs),
     .clk_fs   (clk_fs),