fixup! busybox: Add patch to allow to boot from overlayfs

Author: legionus

external/busybox/patches/0001-switch_root-Allow-to-use-on-overlayfs.patch

@@ -0,0 +1,43 @@
+From 8993e7086444ca9b757b611f98834fa7a4e169c5 Mon Sep 17 00:00:00 2001
+From: Alexey Gladkov <legion@kernel.org>
+Date: Mon, 16 Jun 2025 09:42:16 +0200
+Subject: [PATCH] switch_root: Make filesystem check not fatal
+
+The switch_root utility from util-linux does not fail if rootdev is not
+ramfs/tmpfs but only skips removing content from rootdev [1].
+
+This change increases the compatibility of the switch_root utility
+between busybox and util_linux.
+
+[1] https://web.git.kernel.org/pub/scm/utils/util-linux/util-linux.git/tree/sys-utils/switch_root.c#n198
+
+Signed-off-by: Alexey Gladkov <legion@kernel.org>
+---
+ util-linux/switch_root.c | 8 ++++----
+ 1 file changed, 4 insertions(+), 4 deletions(-)
+
+diff --git a/util-linux/switch_root.c b/util-linux/switch_root.c
+index 14139736e..c3fef628b 100644
+--- a/util-linux/switch_root.c
++++ b/util-linux/switch_root.c
+@@ -245,13 +245,13 @@ int switch_root_main(int argc UNUSED_PARAM, char **argv)
+ 	if ((unsigned)stfs.f_type != RAMFS_MAGIC
+ 	 && (unsigned)stfs.f_type != TMPFS_MAGIC
+ 	) {
+-		bb_simple_error_msg_and_die("root filesystem is not ramfs/tmpfs");
+-	}
+-
+-	if (!dry_run) {
++		bb_simple_error_msg("root filesystem is not ramfs/tmpfs");
++	} else if (!dry_run) {
+ 		// Zap everything out of rootdev
+ 		delete_contents("/", rootdev);
++	}
+ 
++	if (!dry_run) {
+ 		// Overmount / with newdir and chroot into it
+ 		if (mount(".", "/", NULL, MS_MOVE, NULL)) {
+ 			// For example, fails when newroot is not a mountpoint
+-- 
+2.49.0
+

external/busybox/patches/0001-switch_root-Make-filesystem-check-not-fatal.patch

@@ -42,6 +42,7 @@ mkdir -p -- \
 	"$rootdir"/bin \
 	"$rootdir"/dev \
 	"$rootdir"/root \
+	"$rootdir"/sysroot \
 	"$rootdir"/squash \
 	"$rootdir"/usr \
 #