diff --git a/litex/tools/litex_sim.py b/litex/tools/litex_sim.py
index 15eabe030..c35fbcc72 100755
--- a/litex/tools/litex_sim.py
+++ b/litex/tools/litex_sim.py
@@ -490,7 +490,7 @@ def main():
         **soc_kwargs)
     if ram_boot_address is not None:
         if ram_boot_address == 0:
-            ram_boot_address = ram_boot_offset
+            ram_boot_address = conf_soc.mem_map["main_ram"]
         soc.add_constant("ROM_BOOT_ADDRESS", ram_boot_address)
     if args.with_ethernet:
         for i in range(4):