diff --git a/rules/pulpos/default_rules.mk b/rules/pulpos/default_rules.mk
index 3c7ec8a..feb3aa3 100644
--- a/rules/pulpos/default_rules.mk
+++ b/rules/pulpos/default_rules.mk
@@ -141,7 +141,7 @@ endif
 #
 # VSIM Flags
 #
-vsim_flags ?= +ENTRY_POINT=0x1c008080 -dpicpppath /usr/bin/g++ -permit_unmatched_virtual_intf -gBAUDRATE=115200
+vsim_flags ?= +ENTRY_POINT=0x1c008080 -dpicpppath /usr/bin/g++ -permit_unmatched_virtual_intf -gBAUDRATE=115200 -permissive
 ifdef bootmode
 ifeq ($(bootmode), spi)
 vsim_flags += -gSTIM_FROM=SPI_FLASH -gLOAD_L2=STANDALONE -gUSE_S25FS256S_MODEL=1