diff --git a/config/rv32gc/imperas.ic b/config/rv32gc/imperas.ic
index 9e9eef55f..eb4039216 100644
--- a/config/rv32gc/imperas.ic
+++ b/config/rv32gc/imperas.ic
@@ -63,9 +63,6 @@
 --override cpu/scontext_undefined=T
 --override cpu/mcontext_undefined=T
 
-# nonratified mnosie register not implemented
---override cpu/mnoise_undefined=T
-
 # mcause and scause only have 4 lsbs of code and 1 msb of interrupt flag
 #--override cpu/ecode_mask=0x8000000F  # for RV32
 --override cpu/ecode_mask=0x800000000000000F # for RV64
@@ -73,8 +70,6 @@
 # Debug mode not yet supported
 --override cpu/debug_mode=none
 
-# Zkr entropy source and seed register not supported.
---override cpu/Zkr=F
 
 
 --override cpu/reset_address=0x80000000