diff --git a/board/common/overlay-initramfs/init b/board/common/overlay-initramfs/init
index 575d668787..d29c2408fe 100755
--- a/board/common/overlay-initramfs/init
+++ b/board/common/overlay-initramfs/init
@@ -2,9 +2,27 @@
 
 PATH=/bin:/sbin:/usr/bin:/usr/sbin
 
-BOOT_DEV=/dev/mmcblk0p1
-ROOT_DEV=/dev/mmcblk0p2
-DATA_DEV=/dev/mmcblk0p3
+msg() {
+    echo "* $1"
+}
+
+ROOT_DEV=$(cat /proc/cmdline | grep -oE 'root=[/a-z0-9]+' | cut -d '=' -f 2)
+if [[ "$ROOT_DEV" =~ ^([/a-z0-9]+)(p[0-9])$ ]]; then  # e.g. /dev/mmcblk0p2
+    DISK_DEV=${BASH_REMATCH[1]}
+    BOOT_DEV=${DISK_DEV}p1
+    DATA_DEV=${DISK_DEV}p3
+else  # e.g. /dev/sdc2
+    [[ "$ROOT_DEV" =~ ^([/a-z0-9]+)([0-9])$ ]]
+    DISK_DEV=${BASH_REMATCH[1]}
+    BOOT_DEV=${DISK_DEV}1
+    DATA_DEV=${DISK_DEV}3
+fi
+
+msg "Disk device is $DISK_DEV"
+msg "Boot device is $BOOT_DEV"
+msg "Root device is $ROOT_DEV"
+msg "Data device is $DATA_DEV"
+
 
 FW_DIR=/data/.fwupdate
 FW_FILE=firmware.img.gz
@@ -15,10 +33,6 @@ LEGACY_FW_FILE_EXTR=firmware
 
 ROOT_INFO_FILE=root_info
 
-msg() {
-    echo "* $1"
-}
-
 on_exit() {
     msg "Switching to normal boot"
     /remove_initramfs
diff --git a/board/common/overlay/etc/init.d/S00datapart b/board/common/overlay/etc/init.d/S00datapart
index d69d2d37a3..833548572e 100755
--- a/board/common/overlay/etc/init.d/S00datapart
+++ b/board/common/overlay/etc/init.d/S00datapart
@@ -1,12 +1,23 @@
 #!/bin/bash
 
-disk_dev="/dev/mmcblk0"
-data_dev="${disk_dev}p3"
+test -n "$os_version" || source /etc/init.d/base
+
+msg_begin "Detecting disk device"
+root_part=$(cat /proc/cmdline | grep -oE 'root=[/a-z0-9]+' | cut -d '=' -f 2)
+if [[ "$root_part" =~ ^([/a-z0-9]+)(p[0-9])$ ]]; then  # e.g. /dev/mmcblk0p2
+    disk_dev=${BASH_REMATCH[1]}
+    data_dev=${disk_dev}p3
+elif [[ "$root_part" =~ ^([/a-z0-9]+)([0-9])$ ]]; then  # e.g. /dev/sdc2
+    disk_dev=${BASH_REMATCH[1]}
+    data_dev=${disk_dev}3
+else
+    msg_fail "unknown ($root_part)"
+    exit 1
+fi
+msg_done "$disk_dev"
 
 test -b $data_dev && exit 0
 
-test -n "$os_version" || source /etc/init.d/base
-
 case "$1" in
     start)
         msg_begin "Creating data partition"
diff --git a/board/common/overlay/sbin/fwupdate b/board/common/overlay/sbin/fwupdate
index ba1ce32651..196fec76b7 100755
--- a/board/common/overlay/sbin/fwupdate
+++ b/board/common/overlay/sbin/fwupdate
@@ -36,7 +36,7 @@ SYS_VERSION_FILE=/etc/version
 SYS_BOARD_FILE=/etc/board
 OS_CONF=/data/etc/os.conf
 
-BOOT_DEV=/dev/mmcblk0p1
+BOOT_DEV=$(mount | grep /boot | cut -d ' ' -f 1)
 MIN_FREE_DISK=$((500*1024))  # 500 MB
 VER_FILE=version
 ROOT_INFO_FILE=root_info