Reduce the number of bootenv vars

README.md

@@ -10,7 +10,7 @@ https://docs.mono.si/gateway-development-kit/getting-started
 
 ## IMPORTANT NOTES
  * This is not your everyday linux image! It is best suited for users that is already familiar
-   with k8s. For first-timers, you may want to try the default config that gives you a ready-to-used
+   with k8s. For first-timers, you may want to try the default config that gives you a ready-to-use
    cluster then get yourself started from there
 
  * The 3 RJ45 ports are label in eth1, eth2, eth0 respectively by the kernel (left to right)

build.env

@@ -5,8 +5,8 @@ TAG=dev
 
 # The Linux kernel, from NXP
 NXP_VERSION=lf-6.18.2-1.0.0
-CRIO_VERSION=cri-o.arm64.v1.35.2
+CRIO_VERSION=cri-o.arm64.v1.33.3
-KUBE_VERSION=v1.34.1
+KUBE_VERSION=v1.33.3
 
 # Mono's tutorial said fsl-ls1046a-rdb.dtb but our shipped board is not that one
 # We need fsl-ls1046a-rdb-sdk.dtb here

clitools/pkg/controller/osupgrade/handler.go

@@ -3,6 +3,7 @@ package osupgrade
 import (
 	"context"
 	"fmt"
+	"os"
 
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/klog/v2"
@@ -12,6 +13,7 @@ import (
 	"example.com/monok8s/pkg/catalog"
 	"example.com/monok8s/pkg/controller/osimage"
 	"example.com/monok8s/pkg/kube"
+	"example.com/monok8s/pkg/node/uboot"
 )
 
 func HandleOSUpgrade(ctx context.Context, clients *kube.Clients,
@@ -89,7 +91,7 @@ func HandleOSUpgrade(ctx context.Context, clients *kube.Clients,
 
 	imageOptions := osimage.ApplyOptions{
 		URL:               first.URL,
-		TargetPath:        "./out/flash.img",
+		TargetPath:        "/dev/sda?",
 		ExpectedRawSHA256: imageSHA,
 		ExpectedRawSize:   first.Size,
 		BufferSize:        6 * 1024 * 1024,
@@ -128,10 +130,9 @@ func HandleOSUpgrade(ctx context.Context, clients *kube.Clients,
 	}
 
 	klog.Info(result)
-	if err := SetNextBootEnv(ctx, NextBootConfig{
+
-		Key:   "boot_part",
+	cfgPath := os.Getenv("FW_ENV_CONFIG_FILE")
-		Value: "B",
+	if err := uboot.ConfigureNextBoot(ctx, cfgPath); err != nil {
-	}); err != nil {
 		return failProgress(ctx, clients, osup, "set boot env", err)
 	}
 
@@ -145,5 +146,8 @@ func HandleOSUpgrade(ctx context.Context, clients *kube.Clients,
 		return fmt.Errorf("update progress status: %w", err)
 	}
 
+	// TODO: Drain the node here
+	// TODO: Issue Reboot
+
 	return nil
 }

clitools/pkg/node/agent.go

@@ -118,6 +118,16 @@ func applyControlAgentClusterRole(ctx context.Context, kubeClient kubernetes.Int
 			Resources: []string{"osupgrades/status"},
 			Verbs:     []string{"get", "patch", "update"},
 		},
+		{
+			APIGroups: []string{monov1alpha1.Group},
+			Resources: []string{"osupgradeprogresses"},
+			Verbs:     []string{"get", "list", "watch", "create", "patch", "update"},
+		},
+		{
+			APIGroups: []string{monov1alpha1.Group},
+			Resources: []string{"osupgradeprogresses/status"},
+			Verbs:     []string{"get", "list", "watch", "create", "patch", "update"},
+		},
 		{
 			APIGroups: []string{""},
 			Resources: []string{"nodes"},

clitools/pkg/node/uboot/ab.go

@@ -21,10 +21,37 @@ func ConfigureABBoot(ctx context.Context, nctx *node.NodeContext) error {
 	return writer.EnsureBootEnv(ctx, BootEnvConfig{
 		BootSource: "usb",
 		BootPart:   "A",
-		BootDisk:        0,
+	})
-		RootfsAPartNum:  2,
+}
-		RootfsBPartNum:  3,
+
-		DataPartNum:     4,
+// This is called by the agent controller/osupgrade/handler.go
-		LinuxRootPrefix: "/dev/sda",
+func ConfigureNextBoot(ctx context.Context, fwEnvCfgPath string) error {
+
+	exePath, err := os.Executable()
+	if err != nil {
+		return fmt.Errorf("get current executable path: %w", err)
+	}
+
+	writer := NewFWEnvWriter(fwEnvCfgPath, exePath)
+
+	currBootPart, err := writer.GetEnv(ctx, "boot_part")
+	if err != nil {
+		return fmt.Errorf("get boot_part: %w", err)
+	}
+
+	next := "A"
+	if currBootPart == "A" {
+		next = "B"
+
+	}
+
+	currBootSource, err := writer.GetEnv(ctx, "boot_source")
+	if err != nil {
+		return fmt.Errorf("get boot_source: %w", err)
+	}
+
+	return writer.EnsureBootEnv(ctx, BootEnvConfig{
+		BootSource: currBootSource,
+		BootPart:   next,
 	})
 }

clitools/pkg/node/uboot/bootcmd_test.go

@@ -0,0 +1,12 @@
+package uboot
+
+import (
+	"fmt"
+	"testing"
+)
+
+func TestBootCmd(_ *testing.T) {
+
+	cfg := BootEnvConfig{}
+	fmt.Println(cfg.bootCmdOrDefault())
+}

clitools/pkg/node/uboot/bootenvconfig.go

@@ -18,22 +18,6 @@ func (c BootEnvConfig) Validate() error {
 		return fmt.Errorf("invalid boot part %q", c.BootPart)
 	}
 
-	if c.BootDisk < 0 {
-		return fmt.Errorf("invalid boot disk %d", c.BootDisk)
-	}
-	if c.RootfsAPartNum <= 0 {
-		return fmt.Errorf("invalid rootfs A part %d", c.RootfsAPartNum)
-	}
-	if c.RootfsBPartNum <= 0 {
-		return fmt.Errorf("invalid rootfs B part %d", c.RootfsBPartNum)
-	}
-	if c.DataPartNum <= 0 {
-		return fmt.Errorf("invalid data part %d", c.DataPartNum)
-	}
-	if strings.TrimSpace(c.LinuxRootPrefix) == "" {
-		return fmt.Errorf("linux root prefix is required")
-	}
-
 	return nil
 }
 

clitools/pkg/node/uboot/env_writer.go

@@ -126,11 +126,6 @@ func (w *FWEnvWriter) EnsureBootEnv(ctx context.Context, cfg BootEnvConfig) erro
 		{"bootcmd", cfg.bootCmdOrDefault()},
 		{"boot_source", string(cfg.BootSource)},
 		{"boot_part", string(cfg.BootPart)},
-		{"boot_disk", fmt.Sprintf("%d", cfg.BootDisk)},
-		{"rootfs_a_partnum", fmt.Sprintf("%d", cfg.RootfsAPartNum)},
-		{"rootfs_b_partnum", fmt.Sprintf("%d", cfg.RootfsBPartNum)},
-		{"data_partnum", fmt.Sprintf("%d", cfg.DataPartNum)},
-		{"linux_root_prefix", cfg.LinuxRootPrefix},
 	}
 
 	for _, kv := range envs {

clitools/pkg/node/uboot/init.go

@@ -3,6 +3,7 @@ package uboot
 import (
 	"bytes"
 	"context"
+	"errors"
 	"fmt"
 	"k8s.io/klog/v2"
 	"os"
@@ -155,7 +156,7 @@ func ConfigureUBootCommands(ctx context.Context, n *node.NodeContext) error {
 			b.WriteString(trimOutput(a.output, 600))
 			b.WriteString("\n")
 		}
-		return fmt.Errorf(b.String())
+		return errors.New(b.String())
 	}
 
 	klog.Infof("Using: %s", best.config)

clitools/pkg/node/uboot/types.go

@@ -14,11 +14,6 @@ const (
 type BootEnvConfig struct {
 	BootSource string // usb or emmc
 	BootPart   string // A or B
-	BootDisk        int
-	RootfsAPartNum  int
-	RootfsBPartNum  int
-	DataPartNum     int
-	LinuxRootPrefix string // /dev/sda or /dev/mmcblk0p
 	BootCmd    string // optional; defaults to DefaultBootCmd
 }
 
@@ -29,32 +24,52 @@ type FWEnvWriter struct {
 }
 
 const defaultBootCmdTemplate = `
+setenv kernel_addr_r 0xa0000000;
+
+if usb start; then
+    if usb dev 0; then
+        echo "Trying generic USB boot...";
+
+        # Prefer extlinux-style boot
+        if test -e usb 0:1 /boot/extlinux/extlinux.conf; then
+            echo "Found extlinux config on USB";
+            sysboot usb 0:1 any ${kernel_addr_r} /boot/extlinux/extlinux.conf;
+        fi;
+
+        # Fallback: U-Boot script image
+		if test -e usb 0:1 /boot/boot.scr; then
+			echo "Found boot.scr on USB";
+			if load usb 0:1 ${kernel_addr_r} /boot/boot.scr; then
+				source ${kernel_addr_r};
+			fi;
+		fi;
+    fi;
+fi;
+
 if test "${boot_source}" = "usb"; then
     usb start || exit;
     setenv boot_iface usb;
+    usb dev 0 || exit;
 elif test "${boot_source}" = "emmc"; then
-    mmc dev ${boot_disk} || exit;
+    mmc dev 0 || exit;
     setenv boot_iface mmc;
 else
     echo "unsupported boot_source: ${boot_source}";
     exit;
 fi;
 
-setenv kernel_addr_r 0xa0000000;
-
 if test "${boot_part}" = "A"; then
-    setenv rootpart ${rootfs_a_partnum};
+    setenv rootpart 2;
 elif test "${boot_part}" = "B"; then
-    setenv rootpart ${rootfs_b_partnum};
+    setenv rootpart 3;
 else
     echo "unsupported boot_part: ${boot_part}";
     exit;
 fi;
 
-setenv bootdev ${boot_disk}:${rootpart};
+setenv bootdev 0:${rootpart};
-setenv rootdev ${linux_root_prefix}${rootpart};
+setenv rootdev ${boot_source}:${rootpart};
-setenv datadev ${linux_root_prefix}${data_partnum};
 
-setenv bootargs "${bootargs_console} root=${rootdev} data=${datadev} rw rootwait rootfstype=ext4";
+setenv bootargs "${bootargs_console} root=${rootdev} bootpart=${boot_part} rw rootwait rootfstype=ext4";
 ext4load ${boot_iface} ${bootdev} ${kernel_addr_r} /boot/kernel.itb && bootm ${kernel_addr_r};
 `

configs/cluster.env.default

@@ -33,6 +33,18 @@ MKS_INIT_CONTROL_PLANE=yes
 # OSUpgrade agent
 MKS_ENABLE_CONTROL_AGENT=yes
 
+# Boot configs
+# usb, emmc
+MKS_BOOT_SOURCE="usb"
+MKS_BOOT_DEV_PREFIX="/dev/sda"
+
+# Depends on your full disk image. This is the default
+MKS_BOOT_PART=A
+MKS_BOOT_DISK=0
+MKS_ROOTFS_PART_A=2
+MKS_ROOTFS_PART_B=3
+MKS_ROOTFS_PART_D=4
+
 MKS_API_SERVER_ENDPOINT=
 MKS_BOOTSTRAP_TOKEN=
 MKS_DISCOVERY_TOKEN_CA_CERT_HASH=

docs/ota.md

@@ -1,10 +1,12 @@
 ## Upgrade process
 
-We use a CRD with an agent to handle this. Our versions follows upstream's.
+We use an agent to watch the OSUpgrade CRD to handle this. Our image versions follows upstream.
 
 To issue an upgrade. Simply use
 
 kubectl apply -f upgrade.yaml
+
+Example yaml
 ```yaml
 apiVersion: monok8s.io/v1alpha1
 kind: OSUpgrade
@@ -12,8 +14,6 @@ metadata:
   name: "my-ugrade-2"
 spec:
   version: "v1.35.3"
-  imageURL: "https://updates.example.com/monok8s-1.2.3.img.zst"
-  checksum: "sha256:..."
   nodeSelector: {}
   catalog:
     inline: |
@@ -39,7 +39,7 @@ spec:
         - v1.34.0
 ```
 
-catalog accepts URL or ConfigMap
+catalog also accepts URL or ※ConfigMap
 ```yaml
 catalog:
   URL: https://example.com/images.yaml
@@ -48,6 +48,9 @@ catalog:
   ConfigMap: images-cm
 ```
 
+※ ConfigMap requires additional RBAC permission which is not by default. You edit the
+control-agent ClusterRole and add `cnofigmaps: get` to allow this.
+
 Contents should look like this
 ```yaml
 stable: v1.35.1

initramfs/rootfs-extra/init

@@ -42,6 +42,168 @@ wait_for_path() {
     done
 }
 
+get_cmdline_arg() {
+    key="$1"
+    for arg in $(cat /proc/cmdline); do
+        case "$arg" in
+            "$key"=*)
+                echo "${arg#"$key"=}"
+                return 0
+                ;;
+        esac
+    done
+    return 1
+}
+
+# Read KEY=VALUE pairs from /sys/class/block/*/uevent without spawning grep/cut.
+get_uevent_value() {
+    file="$1"
+    want_key="$2"
+
+    [ -f "$file" ] || return 1
+
+    while IFS='=' read -r k v; do
+        [ "$k" = "$want_key" ] && {
+            echo "$v"
+            return 0
+        }
+    done < "$file"
+
+    return 1
+}
+
+# Return the /dev/<partition> path for the first partition whose GPT PARTNAME matches.
+find_first_part_by_partname() {
+    want_label="$1"
+
+    for p in /sys/class/block/*; do
+        [ -f "$p/partition" ] || continue
+
+        partname="$(get_uevent_value "$p/uevent" PARTNAME || true)"
+        [ "$partname" = "$want_label" ] || continue
+
+        devname="$(basename "$p")"
+        echo "/dev/$devname"
+        return 0
+    done
+
+    return 1
+}
+
+wait_for_partnames() {
+    timeout="${1:-3}"
+    shift
+
+    i=0
+    while [ "$i" -lt "$timeout" ]; do
+        all_found=1
+        for name in "$@"; do
+            if ! find_first_part_by_partname "$name" >/dev/null; then
+                all_found=0
+                break
+            fi
+        done
+
+        [ "$all_found" -eq 1 ] && return 0
+
+        sleep 1
+        i=$((i + 1))
+		log "Still waiting for $@ to populate($i)"
+    done
+
+    return 1
+}
+
+find_part_by_partuuid() {
+    want="$1"
+
+    for p in /sys/class/block/*; do
+        [ -f "$p/partition" ] || continue
+
+        partuuid="$(get_uevent_value "$p/uevent" PARTUUID || true)"
+        [ "$partuuid" = "$want" ] || continue
+
+        echo "/dev/$(basename "$p")"
+        return 0
+    done
+
+    return 1
+}
+
+# Return the parent disk name for a partition device name.
+# Examples:
+#   sda2      -> sda
+#   mmcblk0p2 -> mmcblk0
+parent_disk_name_for_part() {
+    part_devname="$1"
+
+    real="$(readlink -f "/sys/class/block/$part_devname")" || return 1
+    parent="$(basename "$(dirname "$real")")" || return 1
+
+    echo "$parent"
+    return 0
+}
+
+# Find a sibling partition on the same disk by GPT PARTNAME.
+find_sibling_part_on_same_disk() {
+    part_path="$1"
+    want_label="$2"
+
+    part_devname="$(basename "$part_path")"
+    disk_devname="$(parent_disk_name_for_part "$part_devname")" || return 1
+
+    for p in /sys/class/block/"$disk_devname"*; do
+        [ -f "$p/partition" ] || continue
+
+        partname="$(get_uevent_value "$p/uevent" PARTNAME || true)"
+        [ "$partname" = "$want_label" ] || continue
+
+        echo "/dev/$(basename "$p")"
+        return 0
+    done
+
+    return 1
+}
+
+# Resolve preferred root device from sysfs.
+# Prefer PARTUUID first, then optionally filesystem UUID if explicitly provided.
+resolve_preferred_root() {
+    pref_root="$1"
+
+    [ -n "$pref_root" ] || return 1
+    find_part_by_partuuid "$pref_root"
+}
+
+# Decide which root PARTNAME we want for the requested slot.
+# Keep a compatibility fallback for legacy "rootfs" as slot A.
+wanted_root_labels_for_slot() {
+    slot="$1"
+
+    case "$slot" in
+        B|b)
+            echo "rootfsB"
+            ;;
+        *)
+            # Try modern rootfsA first, then legacy rootfs
+            echo "rootfsA rootfs"
+            ;;
+    esac
+}
+
+find_fallback_root_for_slot() {
+    slot="$1"
+
+    for label in $(wanted_root_labels_for_slot "$slot"); do
+        dev="$(find_first_part_by_partname "$label" || true)"
+        if [ -n "$dev" ]; then
+            echo "$dev"
+            return 0
+        fi
+    done
+
+    return 1
+}
+
 mkdir -p /dev /proc /sys /run
 mount_or_panic -t devtmpfs devtmpfs /dev
 mount_or_panic -t proc proc /proc
@@ -62,45 +224,56 @@ log "Booting kernel took $(cut -d' ' -f1 /proc/uptime) seconds."
 
 . /etc/build-info || panic "failed to source /etc/build-info"
 
-ROOT_DEV=""
+wait_for_partnames 30 rootfsA rootfsB data || panic "failed to wait for fs"
-DATA_DEV=""
 
-for arg in $(cat /proc/cmdline); do
+ROOT_CMD="$(get_cmdline_arg root || true)"
-    case "$arg" in
+BOOT_PART="$(get_cmdline_arg bootpart || true)"
-        root=*)
+PREFERRED_PARTUUID="$(get_cmdline_arg pref_root || true)"
-            ROOT_DEV="${arg#root=}"
-            ;;
-        data=*)
-            DATA_DEV="${arg#data=}"
-            ;;
-    esac
-done
 
-[ -n "$ROOT_DEV" ] || {
+ROOT_DEV="$(resolve_preferred_root "$PREFERRED_PARTUUID" || true)"
-    log "No root= specified in cmdline"
+if [ -n "$ROOT_DEV" ]; then
-    exec sh
+	log "Using preferred root device: $ROOT_DEV"
-}
+fi
 
-[ -n "$DATA_DEV" ] || {
+if [ -z "$ROOT_DEV" ]; then
-    log "No data= specified in cmdline"
+    ROOT_DEV="$(find_fallback_root_for_slot "$BOOT_PART" || true)"
-    exec sh
+    if [ -n "$ROOT_DEV" ]; then
-}
+        log "Preferred root not found. Falling back to first valid root device: $ROOT_DEV"
+    fi
+fi
 
+[ -n "$ROOT_DEV" ] || panic "no usable root device found"
+
+DATA_DEV="$(find_sibling_part_on_same_disk "$ROOT_DEV" data || true)"
+
+[ -n "$DATA_DEV" ] || panic "no data partition found on same disk as $ROOT_DEV"
+
+wait_for_path "$ROOT_DEV"
 wait_for_path "$DATA_DEV"
 
 e2fsck -p "$DATA_DEV" || {
-    echo "Auto fsck failed, forcing repair"
+    log "Auto fsck failed, forcing repair"
     e2fsck -y "$DATA_DEV" || panic "fsck failed on $DATA_DEV"
 }
 
 mkdir -p /newroot
+mkdir -p /newroot/data
+mkdir -p /newroot/var
+
 mount_retry "$ROOT_DEV" /newroot ext4 ro
 mount_retry "$DATA_DEV" /newroot/data ext4 rw
 
+mkdir -p /newroot/data/var
+mkdir -p /newroot/data/etc-overlay/upper
+mkdir -p /newroot/data/etc-overlay/work
+
 mount_or_panic --bind /newroot/data/var /newroot/var
 
+# BusyBox mount just needs a normal -o option string here.
+# The important bit is that overlayfs itself requires lowerdir/upperdir/workdir,
+# and workdir must live on the same filesystem as upperdir.
 mount_or_panic -t overlay overlay \
-    -o lowerdir=/newroot/etc,upperdir=/newroot/data/etc-overlay/upper,workdir=/newroot/data/etc-overlay/work \
+    -o "lowerdir=/newroot/etc,upperdir=/newroot/data/etc-overlay/upper,workdir=/newroot/data/etc-overlay/work" \
     /newroot/etc
 
 mount_or_panic --move /dev /newroot/dev
@@ -108,7 +281,7 @@ mount_or_panic --move /proc /newroot/proc
 mount_or_panic --move /sys /newroot/sys
 mount_or_panic --move /run /newroot/run
 
-log "Switching root to $ROOT_DEV"
+log "Switching root to $ROOT_DEV (data: $DATA_DEV, slot: $BOOT_PART)"
 exec switch_root /newroot /sbin/init
 
 panic "switch_root returned unexpectedly"

macos/flashusb.sh

@@ -2,10 +2,9 @@
 set -eu
 
 ### User-configurable vars
-IMG="./out/monok8s-dev.img.gz"
+IMG_DIR="./out"
-DEFAULT_DISK="/dev/disk7"         # whole disk, not a partition
 CONFIG_PART_SUFFIX="s1"           # config partition after flashing
-ENV_SEARCH_DIR="./out"            # optional; leave empty to use image dir
+ENV_SEARCH_DIR="./out"            # optional; leave empty to use selected image dir
 
 MNT="/tmp/monok8s-usb-config.$$"
 
@@ -59,6 +58,131 @@ wait_for_mountable_partition() {
     return 1
 }
 
+select_image() {
+    dir="$1"
+
+    [ -d "$dir" ] || die "Image directory not found: $dir"
+
+    OLD_IFS="${IFS}"
+    IFS='
+'
+    set -- $(find "$dir" -maxdepth 1 -type f -name '*.img.gz' | sort)
+    IFS="${OLD_IFS}"
+
+    [ "$#" -gt 0 ] || die "No .img.gz images found in $dir"
+
+    echo "Available images:"
+    n=1
+    for img in "$@"; do
+        size="$(stat -f%z "$img" 2>/dev/null || echo "?")"
+        echo "  [$n] $(basename "$img") (${size} bytes)"
+        n=$((n + 1))
+    done
+
+    echo
+    printf "Select image number: "
+    read -r choice
+
+    case "$choice" in
+        ''|*[!0-9]*)
+            die "Invalid selection: $choice"
+            ;;
+    esac
+
+    n=1
+    for img in "$@"; do
+        if [ "$n" -eq "$choice" ]; then
+            SELECTED_IMG="$img"
+            return 0
+        fi
+        n=$((n + 1))
+    done
+
+    die "Selection out of range: $choice"
+}
+
+list_candidate_disks() {
+    found=0
+    for dev in /dev/disk*; do
+        base="$(basename "$dev")"
+
+        case "$base" in
+            disk[0-9])
+                ;;
+            *)
+                continue
+                ;;
+        esac
+
+        info="$(diskutil list "$dev" 2>/dev/null || true)"
+        [ -n "$info" ] || continue
+
+        # Skip Apple disks
+        echo "$info" | grep -q "APFS" && continue
+
+        info="$(diskutil info "$dev" 2>/dev/null || true)"
+        found=1
+
+        media_name="$(echo "$info" | sed -n 's/^ *Device \/ Media Name: *//p' | head -n1)"
+        protocol="$(echo "$info" | sed -n 's/^ *Protocol: *//p' | head -n1)"
+        size="$(echo "$info" | sed -n 's/^ *Disk Size: *//p' | head -n1)"
+
+        echo "$dev|$media_name|$protocol|$size"
+    done
+
+    [ "$found" -eq 1 ] || return 1
+    return 0
+}
+
+select_disk() {
+    candidates="$(list_candidate_disks || true)"
+
+    if [ -z "$candidates" ]; then
+        warn "No obvious external candidate disks found."
+        printf "Enter target disk manually (example: /dev/disk7): "
+        read -r TARGET_DISK
+        [ -n "$TARGET_DISK" ] || die "No disk entered"
+        return 0
+    fi
+
+    echo "Candidate target disks:"
+    n=1
+    echo "$candidates" | while IFS='|' read -r dev media protocol size; do
+        echo "  [$n] $dev - $media - $protocol - $size"
+        n=$((n + 1))
+    done
+
+    echo
+    printf "Select disk number (or type a full /dev/diskN path): "
+    read -r choice
+
+    case "$choice" in
+        /dev/disk[0-9]*)
+            TARGET_DISK="$choice"
+            return 0
+            ;;
+        ''|*[!0-9]*)
+            die "Invalid selection: $choice"
+            ;;
+    esac
+
+    n=1
+    OLD_IFS="${IFS}"
+    IFS='
+'
+    for line in $candidates; do
+        if [ "$n" -eq "$choice" ]; then
+            TARGET_DISK="$(echo "$line" | cut -d'|' -f1)"
+            IFS="${OLD_IFS}"
+            return 0
+        fi
+        n=$((n + 1))
+    done
+    IFS="${OLD_IFS}"
+
+    die "Selection out of range: $choice"
+}
+
 ### Sanity checks
 require_cmd diskutil
 require_cmd gunzip
@@ -70,24 +194,26 @@ require_cmd cp
 require_cmd sed
 require_cmd stat
 require_cmd pv
+require_cmd cut
+require_cmd grep
+require_cmd head
 
-printf "disk ($DEFAULT_DISK): "
+select_image "$IMG_DIR"
-read -r TARGET_DISK
+IMG="$SELECTED_IMG"
 
-if [ -z "$TARGET_DISK" ]; then
+select_disk
-	TARGET_DISK="$DEFAULT_DISK"
-fi
 
 TARGET_RAW_DISK="/dev/r$(basename "$TARGET_DISK")"
 TARGET_BASENAME="$(basename "$TARGET_DISK")"
 
 ### Derived vars
 TARGET_CONFIG_PART="/dev/${TARGET_BASENAME}${CONFIG_PART_SUFFIX}"
-IMG_DIR="$(cd "$(dirname "$IMG")" && pwd)"
+IMG_DIR_ABS="$(cd "$(dirname "$IMG")" && pwd)"
-SEARCH_DIR="${ENV_SEARCH_DIR:-$IMG_DIR}"
+SEARCH_DIR="${ENV_SEARCH_DIR:-$IMG_DIR_ABS}"
-IMG_SIZE_BYTES="$(stat -f%z "$IMG")"
 
 [ -f "$IMG" ] || die "Image not found: $IMG"
+IMG_SIZE_BYTES="$(stat -f%z "$IMG")"
+
 [ -b "$TARGET_DISK" ] || die "Target disk not found: $TARGET_DISK"
 [ "$(id -u)" -eq 0 ] || die "Run this script with sudo"
 
@@ -122,7 +248,7 @@ diskutil unmountDisk force "$TARGET_DISK" || die "Failed to unmount $TARGET_DISK
 log "Flashing image with progress..."
 pv -s "$IMG_SIZE_BYTES" "$IMG" \
     | gunzip \
-    | dd of="$TARGET_RAW_DISK" bs=1m
+    | dd of="$TARGET_RAW_DISK" bs=4m
 
 log "Syncing writes..."
 sync