diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index a3da383a5..379c491fe 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -115,12 +115,6 @@ jobs:
             tools: opensuse
           - distro: ubuntu
             tools: opensuse
-          # rpm in Debian is currently missing
-          # https://github.com/rpm-software-management/rpm/commit/ea3187cfcf9cac87e5bc5e7db79b0338da9e355e
-          - distro: fedora
-            tools: debian
-          - distro: centos
-            tools: debian
           # This combination results in rpm failing because of SIGPIPE.
           # TODO: Try again once Arch gets a new rpm release.
           - distro: centos
diff --git a/mkosi/installer/__init__.py b/mkosi/installer/__init__.py
index 1a37fee2e..7e8fdce26 100644
--- a/mkosi/installer/__init__.py
+++ b/mkosi/installer/__init__.py
@@ -56,6 +56,7 @@ def mounts(cls, context: Context) -> list[PathString]:
                         Path("/var") / d / subdir / p.relative_to(src),
                     ]
                     for p in caches
+                    if (context.config.package_cache_dir_or_default() / d / subdir / p.relative_to(src)).exists()
                 )
 
         return mounts
diff --git a/mkosi/kmod.py b/mkosi/kmod.py
index 9b2eeeb45..3d8cba725 100644
--- a/mkosi/kmod.py
+++ b/mkosi/kmod.py
@@ -164,6 +164,9 @@ def gen_required_kernel_modules(
     yield modulesd
     yield modulesd / "kernel"
 
+    if (root / "usr/lib/firmware").exists():
+        yield root / "usr/lib/firmware"
+
     for d in (modulesd, root / "usr/lib/firmware"):
         for p in (root / d).rglob("*"):
             if p.is_dir():
diff --git a/mkosi/run.py b/mkosi/run.py
index 4960de4c3..f5a9e0b4e 100644
--- a/mkosi/run.py
+++ b/mkosi/run.py
@@ -210,7 +210,7 @@ def preexec() -> None:
             log_process_failure(cmdline, e.returncode)
         if ARG_DEBUG_SHELL.get():
             subprocess.run(
-                [*sandbox, "sh"],
+                [*sandbox, "bash"],
                 check=False,
                 stdin=sys.stdin,
                 text=True,