diff --git a/ci/svd2rust-regress/src/diff.rs b/ci/svd2rust-regress/src/diff.rs
index b51375b6..de4d0d31 100644
--- a/ci/svd2rust-regress/src/diff.rs
+++ b/ci/svd2rust-regress/src/diff.rs
@@ -235,10 +235,10 @@ impl Diffing {
             ) => last_args.as_deref(),
             None => None,
         });
-        let join = |opt1: Option<&str>, opt2: Option<&str>| -> Option<String> {
+        let join = |opt1: Option<&str>, opt2: Option<&str>| -> Option<Vec<String>> {
             match (opt1, opt2) {
-                (Some(str1), Some(str2)) => Some(format!("{} {}", str1, str2)),
-                (Some(str), None) | (None, Some(str)) => Some(str.to_owned()),
+                (Some(str1), Some(str2)) => vec![str1.to_owned(), str2.to_owned()].into(),
+                (Some(str), None) | (None, Some(str)) => Some(vec![str.to_owned()]),
                 (None, None) => None,
             }
         };
@@ -246,14 +246,14 @@ impl Diffing {
             .setup_case(
                 &opts.output_dir.join("baseline"),
                 &baseline_bin,
-                join(baseline_cmd, last_args).as_deref(),
+                &join(baseline_cmd, last_args),
             )
             .with_context(|| "couldn't create head")?;
         let current = test
             .setup_case(
                 &opts.output_dir.join("current"),
                 &current_bin,
-                join(current_cmd, last_args).as_deref(),
+                &join(current_cmd, last_args),
             )
             .with_context(|| "couldn't create base")?;
 
diff --git a/ci/svd2rust-regress/src/main.rs b/ci/svd2rust-regress/src/main.rs
index 2f3f9d0e..e45e4612 100644
--- a/ci/svd2rust-regress/src/main.rs
+++ b/ci/svd2rust-regress/src/main.rs
@@ -100,7 +100,7 @@ pub struct TestAll {
     #[clap(short = 'p', long = "svd2rust-path", default_value = default_svd2rust())]
     pub current_bin_path: PathBuf,
     #[clap(last = true)]
-    pub command: Option<Vec<String>>,
+    pub passthrough_opts: Option<Vec<String>>,
     // TODO: Specify smaller subset of tests? Maybe with tags?
     // TODO: Compile svd2rust?
 }
@@ -149,7 +149,7 @@ pub struct Test {
     #[clap(short = 'p', long = "svd2rust-path", default_value = default_svd2rust())]
     pub current_bin_path: PathBuf,
     #[clap(last = true)]
-    pub command: Option<Vec<String>>,
+    pub passthrough_opts: Option<Vec<String>>,
 }
 
 impl Test {
@@ -191,7 +191,7 @@ impl Test {
                 .ok_or_else(|| anyhow::anyhow!("no test found for chip"))?
                 .to_owned()
         };
-        test.test(opts, &self.current_bin_path, &self.command)?;
+        test.test(opts, &self.current_bin_path, &self.passthrough_opts)?;
         Ok(())
     }
 }
@@ -247,7 +247,7 @@ impl TestAll {
         tests.par_iter().for_each(|t| {
             let start = Instant::now();
 
-            match t.test(opt, &self.current_bin_path, &self.command) {
+            match t.test(opt, &self.current_bin_path, &self.passthrough_opts) {
                 Ok(s) => {
                     if let Some(stderrs) = s {
                         let mut buf = String::new();