diff --git a/src/shared/dissect-image.c b/src/shared/dissect-image.c
index e2baa4497c..c29d70fa04 100644
--- a/src/shared/dissect-image.c
+++ b/src/shared/dissect-image.c
@@ -111,11 +111,23 @@ not_found:
 /* Detect RPMB and Boot partitions, which are not listed by blkid.
  * See https://github.com/systemd/systemd/issues/5806. */
 static bool device_is_mmc_special_partition(struct udev_device *d) {
-        const char *sysname = udev_device_get_sysname(d);
+        const char *sysname;
+
+        sysname = udev_device_get_sysname(d);
         return (sysname && startswith(sysname, "mmcblk") &&
                 (endswith(sysname, "rpmb") || endswith(sysname, "boot0") || endswith(sysname, "boot1")));
 }
 
+static bool device_is_block(struct udev_device *d) {
+        const char *ss;
+
+        ss = udev_device_get_subsystem(d);
+        if (!ss)
+                return false;
+
+        return streq(ss, "block");
+}
+
 int dissect_image(
                 int fd,
                 const void *root_hash,
@@ -289,11 +301,19 @@ int dissect_image(
                 first = udev_enumerate_get_list_entry(e);
                 udev_list_entry_foreach(item, first) {
                         _cleanup_udev_device_unref_ struct udev_device *q;
+                        dev_t qn;
 
                         q = udev_device_new_from_syspath(udev, udev_list_entry_get_name(item));
                         if (!q)
                                 return -errno;
 
+                        qn = udev_device_get_devnum(q);
+                        if (major(qn) == 0)
+                                continue;
+
+                        if (!device_is_block(q))
+                                continue;
+
                         if (device_is_mmc_special_partition(q))
                                 continue;
                         n++;
@@ -371,6 +391,9 @@ int dissect_image(
                 if (st.st_rdev == qn)
                         continue;
 
+                if (!device_is_block(q))
+                        continue;
+
                 if (device_is_mmc_special_partition(q))
                         continue;