diff --git a/main/postmarketos-mkinitfs/APKBUILD b/main/postmarketos-mkinitfs/APKBUILD
index 20972de00..a328c52d4 100644
--- a/main/postmarketos-mkinitfs/APKBUILD
+++ b/main/postmarketos-mkinitfs/APKBUILD
@@ -1,6 +1,6 @@
 # Maintainer: Oliver Smith <ollieparanoid@postmarketos.org>
 pkgname=postmarketos-mkinitfs
-pkgver=0.20
+pkgver=0.21
 pkgrel=0
 pkgdesc="Tool to generate initramfs images for postmarketOS"
 url="https://postmarketos.org"
@@ -55,7 +55,7 @@ check() {
 
 sha512sums="5037cb7285bb7c0c40ca9e6df332d882ef9a8b379756c785f921e062dab1b7e7f3139d00897f69323a916d709ced4297fea8cbd3a13ebae575b873ec9e2cbfae  00-default.modules
 bafd06286594102b8b3b126c3ae0a77a97f004ab804f03426154310c5107a1acaf3636bdba92626333adfe4fb0df32ff42c6d8d9e7adf35f6da620c6e14407a1  init.sh.in
-e4b5bb7206a4a8f99a23414d6830ccf6ecaf2990ca4923842e99fa14dc50a0a4ae88e0368129b423f9e7e7b446f25b641ad629b7aa08682f269aed7a234762cb  init_functions.sh
+7e44c39393587e73d69533eb58362245bcb6cdb28a91eadd7878af54831b0c0ab264e8e9984b138e68b207d1f7544adab2b64b6ec68b4f528ea1273819670210  init_functions.sh
 dfc01ee0547ea88b7aa45a005e842b636e9e19bbf1705f3dad53a66d57af7c5c513c092b5469a06d9b00322e56a4d25f1b47e4c5324aafa99f5291679968d1f1  mkinitfs.sh
 6a034e52e7e0d2eb4db632d1a08a47e58ccfc82780e3d1fbc08759ae0c7a1c7c6a222ad91fe346c45d82bec4487cc9c4b71adad96061865153c0e98e1e8e1c37  mkinitfs_functions.sh
 c7a3c33daeb12b33ac72207191941c4d634f15c22958273b52af381a70ebaba1d3a9299483f0c447d9e66c560151fe7b9588bb4bbef2c8914f83185984ee4622  mkinitfs_test.sh"
diff --git a/main/postmarketos-mkinitfs/init_functions.sh b/main/postmarketos-mkinitfs/init_functions.sh
index 362c4ca2a..79566964e 100644
--- a/main/postmarketos-mkinitfs/init_functions.sh
+++ b/main/postmarketos-mkinitfs/init_functions.sh
@@ -60,7 +60,7 @@ setup_mdev() {
 mount_subpartitions() {
 	# Do not create subpartition mappings if pmOS_boot
 	# already exists (e.g. installed on an sdcard)
-	blkid |grep -q "pmOS_boot"  && return
+	[ -n "$(find_boot_partition)" ] && return
 	attempt_count=0
 	echo "Trying to mount subpartitions for 10 seconds..."
 	while [ -z "$(find_boot_partition)" ]; do
@@ -74,7 +74,7 @@ mount_subpartitions() {
 					# Ensure that this was the *correct* subpartition
 					# Some devices have mmc partitions that appear to have
 					# subpartitions, but aren't our subpartition.
-					if blkid | grep -q "pmOS_boot"; then
+					if [ -n "$(find_boot_partition)" ]; then
 						break
 					fi
 					kpartx -d "$partition"
@@ -161,7 +161,7 @@ find_boot_partition() {
 		echo "${x#pmos_boot=}"
 		return
 	done
-	findfs LABEL="pmOS_boot"
+	findfs LABEL="pmOS_inst_boot" || findfs LABEL="pmOS_boot"
 }
 
 # $1: path