diff --git a/sim/imperas.ic b/sim/imperas.ic
index 6a34466f..3744a426 100644
--- a/sim/imperas.ic
+++ b/sim/imperas.ic
@@ -6,6 +6,7 @@
 --override cpu/ignore_non_leaf_DAU=1
 --override cpu/wfi_is_nop=T
 --override cpu/mimpid=0x100
+--override cpu/misa_Extensions_mask=0x0
 
 # THIS NEEDS FIXING to 16
 --override cpu/PMP_registers=0
diff --git a/testbench/testbench_imperas.sv b/testbench/testbench_imperas.sv
index 27bd1246..6ac11bc2 100644
--- a/testbench/testbench_imperas.sv
+++ b/testbench/testbench_imperas.sv
@@ -178,8 +178,7 @@ module testbench;
           void'(rvviRefMemorySetVolatile(`GPIO_BASE, (`GPIO_BASE + `GPIO_RANGE)));
       end
       if (`UART_SUPPORTED) begin
-          //void'(rvviRefMemorySetVolatile(`UART_BASE, (`UART_BASE + `UART_RANGE)));
-          void'(rvviRefMemorySetVolatile(`UART_BASE, (`UART_BASE + 7))); // BUG
+          void'(rvviRefMemorySetVolatile(`UART_BASE, (`UART_BASE + `UART_RANGE)));
       end
       if (`PLIC_SUPPORTED) begin
           void'(rvviRefMemorySetVolatile(`PLIC_BASE, (`PLIC_BASE + `PLIC_RANGE)));