--- /usr/portage/sys-fs/cryptsetup/files/2.4.3-dmcrypt.rc	2022-10-31 17:40:24.000000000 +0000
+++ /etc/init.d/dmcrypt	2022-11-12 16:30:56.337988823 +0000
@@ -58,7 +58,7 @@
 		return
 	fi
 
-	if [ -n "${header}" ] ; then
+	if [ -n "${header}" ] && [ -z "${remdev}" ] ; then
 		header_opt="--header=${header}"
 
 		i=0
@@ -71,6 +71,41 @@
 			ewarn "Waited ${i} times for header file ${header}. Aborting ${target}."
 			return
 		fi
+    # handle header on removable device
+    elif [ -n "${header}" ] && [ -n "${remdev}" ] ; then
+        # temp directory to mount removable device
+        local mntrem="${RC_SVCDIR}/dm-crypt-remdev-header.$$"
+        if [ ! -d "${mntrem}" ] ; then
+            if ! mkdir -p "${mntrem}" ; then
+                ewarn "${source} will not be decrypted ..."
+                einfo "Reason: Unable to create temporary mount point '${mntrem}'"
+                return
+            fi
+        fi
+        i=0
+        einfo "Please insert removable device for ${target}"
+        while [ ${i} -lt ${dmcrypt_max_timeout} ] ; do
+            foo=""
+            if mount -n -o ro "${remdev}" "${mntrem}" 2>/dev/null >/dev/null ; then
+                # header exists?
+                if [ ! -e "${mntrem}${header}" ] ; then
+                    umount -n "${mntrem}"
+                    rmdir "${mntrem}"
+                    einfo "Cannot find ${header} on removable media."
+                    read_abort "Abort" ${dmcrypt_key_timeout} && return
+                else
+                    header="${mntrem}${header}"
+                    break
+                fi
+            else
+                [ -e "${remdev}" ] \
+                    && foo="mount failed" \
+                    || foo="mount source not found"
+            fi
+            : $((i += 1))
+            read_abort "Stop waiting after $i attempts (${foo})" -t 1 && return
+        done
+        header_opt="--header ${header}"
 	else
 		header_opt=""
 	fi
@@ -96,6 +131,32 @@
 		losetup ${source} ${loop_file}
 	fi
 
+	read_abort() {
+		# some colors
+		local ans savetty resettty
+		[ -z "${NORMAL}" ] && eval $(eval_ecolors)
+		einfon "  $1? (${WARN}yes${NORMAL}/${GOOD}No${NORMAL}) "
+		shift
+		# This is ugly as s**t.  But POSIX doesn't provide `read -t`, so
+		# we end up having to implement our own crap with stty/etc...
+		savetty=$(stty -g)
+		resettty='stty ${savetty}; trap - EXIT HUP INT TERM'
+		trap 'eval "${resettty}"' EXIT HUP INT TERM
+		stty -icanon
+		stty min 0 time "$(( $2 * 10 ))"
+		ans=$(dd count=1 bs=1 2>/dev/null) || ans=''
+		eval "${resettty}"
+		if [ -z "${ans}" ] ; then
+			printf '\r'
+		else
+			echo
+		fi
+		case ${ans} in
+			[yY]) return 0;;
+			*) return 1;;
+		esac
+	}
+
 	# cryptsetup:
 	# open   <device> <name>      # <device> is $source
 	# create <name>   <device>    # <name>   is $target
@@ -118,32 +179,6 @@
 
 	# Handle keys
 	if [ -n "${key}" ] ; then
-		read_abort() {
-			# some colors
-			local ans savetty resettty
-			[ -z "${NORMAL}" ] && eval $(eval_ecolors)
-			einfon "  $1? (${WARN}yes${NORMAL}/${GOOD}No${NORMAL}) "
-			shift
-			# This is ugly as s**t.  But POSIX doesn't provide `read -t`, so
-			# we end up having to implement our own crap with stty/etc...
-			savetty=$(stty -g)
-			resettty='stty ${savetty}; trap - EXIT HUP INT TERM'
-			trap 'eval "${resettty}"' EXIT HUP INT TERM
-			stty -icanon
-			stty min 0 time "$(( $2 * 10 ))"
-			ans=$(dd count=1 bs=1 2>/dev/null) || ans=''
-			eval "${resettty}"
-			if [ -z "${ans}" ] ; then
-				printf '\r'
-			else
-				echo
-			fi
-			case ${ans} in
-				[yY]) return 0;;
-				*) return 1;;
-			esac
-		}
-
 		# Notes: sed not used to avoid case where /usr partition is encrypted.
 		mode=${key##*:} && ( [ "${mode}" = "${key}" ] || [ -z "${mode}" ] ) && mode=reg
 		key=${key%:*}
@@ -266,7 +301,7 @@
 
 start() {
 	local print_header=true cryptfs_status=0
-	local gpg_options key loop_file target targetline options pre_mount post_mount source swap remdev
+	local gpg_options key loop_file target targetline options pre_mount post_mount source swap remdev header
 
 	local x
 	for x in $(cat /proc/cmdline) ; do