--- zzzz-none-000/linux-4.4.271/block/partitions/efi.c	2021-06-03 06:22:09.000000000 +0000
+++ hawkeye-5590-750/linux-4.4.271/block/partitions/efi.c	2023-04-19 10:22:28.000000000 +0000
@@ -103,12 +103,15 @@
 #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
  * the partition tables happens after init too.
  */
 static int force_gpt;
+static char saved_rootfs_name[64];
+
 static int __init
 force_gpt_fn(char *str)
 {
@@ -117,6 +120,12 @@
 }
 __setup("gpt", force_gpt_fn);
 
+static int __init rootfs_name_setup(char *line)
+{
+	strlcpy(saved_rootfs_name, line, sizeof(saved_rootfs_name));
+	return 1;
+}
+__setup("rootfsname=", rootfs_name_setup);
 
 /**
  * efi_crc32() - EFI version of crc32 function
@@ -696,6 +705,9 @@
 	u32 i;
 	unsigned ssz = bdev_logical_block_size(state->bdev) / 512;
 
+	if (!saved_rootfs_name[0])
+		strlcpy(saved_rootfs_name, "rootfs", sizeof("rootfs"));
+
 	if (!find_valid_gpt(state, &gpt, &ptes) || !gpt || !ptes) {
 		kfree(gpt);
 		kfree(ptes);
@@ -735,6 +747,15 @@
 			info->volname[label_count] = c;
 			label_count++;
 		}
+
+		if (ROOT_DEV == 0 &&
+		    !strcmp(info->volname, saved_rootfs_name) &&
+		    config_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);