diff --git a/niar/cmdrunner.py b/niar/cmdrunner.py
index 07422d8..06ab3d2 100644
--- a/niar/cmdrunner.py
+++ b/niar/cmdrunner.py
@@ -5,7 +5,7 @@ import subprocess
 
 from .logging import logger
 
-__all__ = ["CompilationUnit", "CommandRunner"]
+__all__ = ["CompilationUnit", "CommandRunner", "CommandFailedError"]
 
 
 class CompilationUnit:
@@ -76,6 +76,8 @@ class CompilationUnit:
                 with open(inf, "rb") as f:
                     r[str(inf)] = f.read()
         return r
+
+
 class CommandRunner:
     cus: list[CompilationUnit]
 
@@ -128,7 +130,7 @@ class CommandRunner:
             logger.error("the following process(es) failed:")
             for cu in failed:
                 logger.error(f"  {formatted(cu)}")
-            raise RuntimeError(f"failed {step} step")
+            raise CommandFailedError(f"failed {step} step")
 
         for cu, _ in runnables:
             cu.mark_up_to_date()
@@ -144,6 +146,10 @@ class CommandRunner:
         logger.info(f"{action} {formatted(cu)}")
 
 
+class CommandFailedError(RuntimeError):
+    pass
+
+
 def formatted(cu):
     if inspect.isfunction(cu.cmd):
         return cu.cmd.__name__
diff --git a/niar/cxxrtl.py b/niar/cxxrtl.py
index 974e42a..9aad1fc 100644
--- a/niar/cxxrtl.py
+++ b/niar/cxxrtl.py
@@ -12,7 +12,7 @@ from amaranth._toolchain.yosys import find_yosys
 from amaranth.back import rtlil
 
 from .build import construct_top
-from .cmdrunner import CommandRunner
+from .cmdrunner import CommandRunner, CommandFailedError
 from .logging import logtime, logger
 from .project import Project
 
@@ -251,7 +251,11 @@ def main(np: Project, args):
                 infs=cc_o_paths + list(np.path("cxxrtl").glob("**/*.zig")),
                 outf=outf,
                 chdir="cxxrtl")
-            cr.run()
+            try:
+                cr.run()
+            except CommandFailedError:
+                logger.log(logging.INFO, "aborting on CommandFailedError")
+                return
             shutil.copy(outf, exe_o_path)
         else:
             cmd = [
@@ -266,7 +270,11 @@ def main(np: Project, args):
             cr.add_process(cmd,
                 infs=cc_o_paths,
                 outf=exe_o_path)
-            cr.run()
+            try:
+                cr.run()
+            except CommandFailedError:
+                logger.log(logging.INFO, "aborting on CommandFailedError")
+                return
 
     if not args.compile:
         cmd = [exe_o_path]