--- zzzz-none-000/linux-5.4.213/block/partitions/efi.c	2022-09-15 10:04:56.000000000 +0000
+++ alder-5690pro-762/linux-5.4.213/block/partitions/efi.c	2024-08-14 09:01:35.000000000 +0000
@@ -89,6 +89,7 @@
 #include <linux/slab.h>
 #include "check.h"
 #include "efi.h"
+#include <linux/root_dev.h>
 
 /* This allows a kernel command line option 'gpt' to override
  * the test for invalid PMBR.  Not __initdata because reloading
@@ -721,6 +722,14 @@
 			info->volname[label_count] = c;
 			label_count++;
 		}
+
+		if (ROOT_DEV == 0 && !strcmp(info->volname, "rootfs") &&
+		    IS_ENABLED(CONFIG_MTD_ROOTFS_ROOT_DEV)) {
+			ROOT_DEV = MKDEV(MAJOR(state->bdev->bd_dev), i + 1);
+			pr_notice("GPT: device [%d:%d] (%s) set to be root filesystem\n",
+				MAJOR(ROOT_DEV), MINOR(ROOT_DEV),
+				info->volname);
+		}
 		state->parts[i + 1].has_info = true;
 	}
 	kfree(ptes);