From: Jan Kiszka <jan.kiszka@siemens.com>

As an eMMC block device image may consist of more than just the user
data partition, provide a helper script that can compose the image from
boot partitions, an RPMB partition and the user data image. The script
also does the required size validation and/or rounding.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
---
 scripts/mkemmc.sh | 185 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 185 insertions(+)
 create mode 100755 scripts/mkemmc.sh

diff --git a/scripts/mkemmc.sh b/scripts/mkemmc.sh
new file mode 100755
index 0000000000..5d40c2889b
--- /dev/null
+++ b/scripts/mkemmc.sh
@@ -0,0 +1,185 @@
+#!/bin/sh -e
+#
+# Create eMMC block device image from boot, RPMB and user data images
+#
+# Copyright (c) Siemens, 2025
+#
+# Authors:
+#  Jan Kiszka <jan.kiszka@siemens.com>
+#
+# This work is licensed under the terms of the GNU GPL version 2.
+# See the COPYING file in the top-level directory.
+#
+
+usage() {
+    echo "$0 [OPTIONS] USER_IMG[:SIZE] OUTPUT_IMG"
+    echo ""
+    echo "SIZE must be a power of 2. If no SIZE is specified, the size of USER_ING will"
+    echo "be used (rounded up)."
+    echo ""
+    echo "Supported options:"
+    echo "  -b BOOT1_IMG[:SIZE]   Add boot partitions. SIZE must be multiples of 128K. If"
+    echo "                          no SIZE is specified, the size of BOOT_IMG will be"
+    echo "                          used (rounded up). BOOT1_IMG will be stored in boot"
+    echo "                          partition 1, and a boot partition 2 of the same size"
+    echo "                          will be created as empty (all zeros) unless -B is"
+    echo "                          specified as well."
+    echo "  -B BOOT2_IMG          Fill boot partition 2 with BOOT2_IMG. Must be combined"
+    echo "                          with -b which is also defining the partition size."
+    echo "  -r RPMB_IMG[:SIZE]    Add RPMB partition. SIZE must be multiples of 128K. If"
+    echo "                          no SIZE is specified, the size of RPMB_IMG will be"
+    echo "                          used (rounded up)."
+    echo "  -h, --help            This help"
+    echo ""
+    echo "All SIZE parameters support the units K, M, G. If SIZE is smaller than the"
+    echo "associated image, it will be truncated in the output image."
+    exit "$1"
+}
+
+process_size() {
+    if [ "${4#*:}" = "$4"  ]; then
+        if ! size=$(stat -L -c %s "$2" 2>/dev/null); then
+            echo "Missing $1 image '$2'." >&2
+            exit 1
+        fi
+        if [ "$3" = 128 ]; then
+            size=$(( (size + 128 * 1024 - 1) & ~(128 * 1024 - 1) ))
+        elif [ $(( size & (size - 1) )) -gt 0 ]; then
+            n=0
+            while [ "$size" -gt 0 ]; do
+                size=$((size >> 1))
+                n=$((n + 1))
+            done
+            size=$((1 << n))
+        fi
+    else
+        value="${4#*:}"
+        if [ "${value%K}" != "$value" ]; then
+            size=${value%K}
+            multiplier=1024
+        elif [ "${value%M}" != "$value" ]; then
+            size=${value%M}
+            multiplier=$((1024 * 1024))
+        elif [ "${value%G}" != "$value" ]; then
+            size=${value%G}
+            multiplier=$((1024 * 1024 * 1024))
+        else
+            size=$value
+            multiplier=1
+        fi
+        if [ "$size" -eq "$size" ] 2>/dev/null; then
+            size=$((size * multiplier))
+        else
+            echo "Invalid value '$value' specified for $2 image size." >&2
+            exit 1
+        fi
+        if [ "$3" = 128 ]; then
+            if [ $(( size & (128 * 1024 - 1) )) -ne 0 ]; then
+                echo "The $2 image size must be multiples of 128K." >&2
+                exit 1
+            fi
+        elif [ $(( size & (size - 1) )) -gt 0 ]; then
+            echo "The %2 image size must be power of 2." >&2
+            exit 1
+        fi
+    fi
+    echo $size
+}
+
+userimg=
+outimg=
+bootimg1=
+bootimg2=/dev/zero
+bootsz=0
+rpmbimg=
+rpmbsz=0
+
+while [ $# -gt 0 ]; do
+    case "$1" in
+        -b)
+            shift
+            [ $# -ge 1 ] || usage 1
+            bootimg1=${1%%:*}
+            bootsz=$(process_size boot "$bootimg1" 128 "$1")
+            shift
+            ;;
+        -B)
+            shift
+            [ $# -ge 1 ] || usage 1
+            bootimg2=$1
+            shift
+            ;;
+        -r)
+            shift
+            [ $# -ge 1 ] || usage 1
+            rpmbimg=${1%%:*}
+            rpmbsz=$(process_size RPMB "$rpmbimg" 128 "$1")
+            shift
+            ;;
+        -h|--help)
+            usage 0
+            ;;
+        *)
+            if [ -z "$userimg" ]; then
+                userimg=${1%%:*}
+                usersz=$(process_size user "$userimg" 2 "$1")
+            elif [ -z "$outimg" ]; then
+                outimg=$1
+            else
+                usage 1
+            fi
+            shift
+            ;;
+    esac
+done
+
+[ -n "$outimg" ] || usage 1
+
+if [ "$bootsz" -gt $((32640 * 1024)) ]; then
+    echo "Boot image size is larger than 32640K." >&2
+    exit 1
+fi
+if [ "$rpmbsz" -gt $((16384 * 1024)) ]; then
+    echo "RPMB image size is larger than 16384K." >&2
+    exit 1
+fi
+
+echo "Creating eMMC image"
+
+truncate "$outimg" -s 0
+pos=0
+
+if [ "$bootsz" -gt 0 ]; then
+    echo "  Boot partition 1 and 2:   $((bootsz / 1024))K each"
+    blocks=$(( bootsz / (128 * 1024) ))
+    dd if="$bootimg1" of="$outimg" conv=sparse bs=128K count=$blocks \
+        status=none
+    dd if="$bootimg2" of="$outimg" conv=sparse bs=128K count=$blocks \
+        seek=$blocks status=none
+    pos=$((2 * bootsz))
+fi
+
+if [ "$rpmbsz" -gt 0 ]; then
+    echo "  RPMB partition:           $((rpmbsz / 1024))K"
+    blocks=$(( rpmbsz / (128 * 1024) ))
+    dd if="$rpmbimg" of="$outimg" conv=sparse bs=128K count=$blocks \
+        seek=$(( pos / (128 * 1024) )) status=none
+    pos=$((pos + rpmbsz))
+fi
+
+if [ "$usersz" -lt 1024 ]; then
+    echo "  User data:                $usersz bytes"
+elif [ "$usersz" -lt $((1024 * 1024)) ]; then
+    echo "  User data:                $(( (usersz + 1023) / 1024 ))K ($usersz)"
+elif [ "$usersz" -lt $((1024 * 1024 * 1024)) ]; then
+    echo "  User data:                $(( (usersz + 1048575) / 1048576))M ($usersz)"
+else
+    echo "  User data:                $(( (usersz + 1073741823) / 1073741824))G ($usersz)"
+fi
+dd if="$userimg" of="$outimg" conv=sparse bs=128K seek=$(( pos / (128 * 1024) )) \
+    count=$(( (usersz + 128 * 1024 - 1) / (128 * 1024) )) status=none
+pos=$((pos + usersz))
+truncate "$outimg" -s $pos
+
+echo ""
+echo "Instantiate via '-device emmc,boot-partition-size=$bootsz,rpmb-partition-size=$rpmbsz,drive=$outimg'"
-- 
2.43.0

Hi Jan,


On 8/24/25 09:18, Jan Kiszka wrote:
> From: Jan Kiszka <jan.kiszka@siemens.com>
> 
> As an eMMC block device image may consist of more than just the user
> data partition, provide a helper script that can compose the image from
> boot partitions, an RPMB partition and the user data image. The script
> also does the required size validation and/or rounding.
> 
> Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
> ---
>  scripts/mkemmc.sh | 185 ++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 185 insertions(+)
>  create mode 100755 scripts/mkemmc.sh
> 
> diff --git a/scripts/mkemmc.sh b/scripts/mkemmc.sh
> new file mode 100755
> index 0000000000..5d40c2889b
> --- /dev/null
> +++ b/scripts/mkemmc.sh
> @@ -0,0 +1,185 @@
> +#!/bin/sh -e
> +#
> +# Create eMMC block device image from boot, RPMB and user data images
> +#
> +# Copyright (c) Siemens, 2025
> +#
> +# Authors:
> +#  Jan Kiszka <jan.kiszka@siemens.com>
> +#
> +# This work is licensed under the terms of the GNU GPL version 2.
> +# See the COPYING file in the top-level directory.
> +#
> +
> +usage() {
> +    echo "$0 [OPTIONS] USER_IMG[:SIZE] OUTPUT_IMG"
> +    echo ""
> +    echo "SIZE must be a power of 2. If no SIZE is specified, the size of USER_ING will"
> +    echo "be used (rounded up)."
> +    echo ""
> +    echo "Supported options:"
> +    echo "  -b BOOT1_IMG[:SIZE]   Add boot partitions. SIZE must be multiples of 128K. If"
> +    echo "                          no SIZE is specified, the size of BOOT_IMG will be"

the size of BOOT1_IMG

> +    echo "                          used (rounded up). BOOT1_IMG will be stored in boot"
> +    echo "                          partition 1, and a boot partition 2 of the same size"
> +    echo "                          will be created as empty (all zeros) unless -B is"
> +    echo "                          specified as well."
> +    echo "  -B BOOT2_IMG          Fill boot partition 2 with BOOT2_IMG. Must be combined"
> +    echo "                          with -b which is also defining the partition size."
> +    echo "  -r RPMB_IMG[:SIZE]    Add RPMB partition. SIZE must be multiples of 128K. If"
> +    echo "                          no SIZE is specified, the size of RPMB_IMG will be"
> +    echo "                          used (rounded up)."
> +    echo "  -h, --help            This help"
> +    echo ""
> +    echo "All SIZE parameters support the units K, M, G. If SIZE is smaller than the"
> +    echo "associated image, it will be truncated in the output image."
> +    exit "$1"
> +}
> +
> +process_size() {
> +    if [ "${4#*:}" = "$4"  ]; then
> +        if ! size=$(stat -L -c %s "$2" 2>/dev/null); then
> +            echo "Missing $1 image '$2'." >&2
> +            exit 1
> +        fi
> +        if [ "$3" = 128 ]; then
> +            size=$(( (size + 128 * 1024 - 1) & ~(128 * 1024 - 1) ))
> +        elif [ $(( size & (size - 1) )) -gt 0 ]; then
> +            n=0
> +            while [ "$size" -gt 0 ]; do
> +                size=$((size >> 1))
> +                n=$((n + 1))
> +            done
> +            size=$((1 << n))
> +        fi
> +    else
> +        value="${4#*:}"
> +        if [ "${value%K}" != "$value" ]; then
> +            size=${value%K}
> +            multiplier=1024
> +        elif [ "${value%M}" != "$value" ]; then
> +            size=${value%M}
> +            multiplier=$((1024 * 1024))
> +        elif [ "${value%G}" != "$value" ]; then
> +            size=${value%G}
> +            multiplier=$((1024 * 1024 * 1024))
> +        else
> +            size=$value
> +            multiplier=1
> +        fi
> +        if [ "$size" -eq "$size" ] 2>/dev/null; then
> +            size=$((size * multiplier))
> +        else
> +            echo "Invalid value '$value' specified for $2 image size." >&2
> +            exit 1
> +        fi
> +        if [ "$3" = 128 ]; then
> +            if [ $(( size & (128 * 1024 - 1) )) -ne 0 ]; then
> +                echo "The $2 image size must be multiples of 128K." >&2
> +                exit 1
> +            fi
> +        elif [ $(( size & (size - 1) )) -gt 0 ]; then
> +            echo "The %2 image size must be power of 2." >&2
> +            exit 1
> +        fi
> +    fi
> +    echo $size
> +}
> +
> +userimg=
> +outimg=
> +bootimg1=
> +bootimg2=/dev/zero
> +bootsz=0
> +rpmbimg=
> +rpmbsz=0
> +
> +while [ $# -gt 0 ]; do
> +    case "$1" in
> +        -b)
> +            shift
> +            [ $# -ge 1 ] || usage 1
> +            bootimg1=${1%%:*}
> +            bootsz=$(process_size boot "$bootimg1" 128 "$1")
> +            shift
> +            ;;
> +        -B)
> +            shift
> +            [ $# -ge 1 ] || usage 1
> +            bootimg2=$1
> +            shift
> +            ;;
> +        -r)
> +            shift
> +            [ $# -ge 1 ] || usage 1
> +            rpmbimg=${1%%:*}
> +            rpmbsz=$(process_size RPMB "$rpmbimg" 128 "$1")
> +            shift
> +            ;;
> +        -h|--help)
> +            usage 0
> +            ;;
> +        *)
> +            if [ -z "$userimg" ]; then
> +                userimg=${1%%:*}
> +                usersz=$(process_size user "$userimg" 2 "$1")
> +            elif [ -z "$outimg" ]; then
> +                outimg=$1
> +            else
> +                usage 1
> +            fi
> +            shift
> +            ;;
> +    esac
> +done
> +
> +[ -n "$outimg" ] || usage 1
> +
> +if [ "$bootsz" -gt $((32640 * 1024)) ]; then
> +    echo "Boot image size is larger than 32640K." >&2
> +    exit 1
> +fi

Should we warn if BOOT1_IMG and/or BOOT2_IMG are truncated as a result
of $bootsz being too small? I can see how providing a larger size can be
useful to be able to later extend the filesystem, but a smaller size is
more likely to indicate an error I suppose?

> +if [ "$rpmbsz" -gt $((16384 * 1024)) ]; then
> +    echo "RPMB image size is larger than 16384K." >&2
> +    exit 1
> +fi> +
> +echo "Creating eMMC image"
> +
> +truncate "$outimg" -s 0
> +pos=0
> +
> +if [ "$bootsz" -gt 0 ]; then
> +    echo "  Boot partition 1 and 2:   $((bootsz / 1024))K each"
> +    blocks=$(( bootsz / (128 * 1024) ))
> +    dd if="$bootimg1" of="$outimg" conv=sparse bs=128K count=$blocks \
> +        status=none
> +    dd if="$bootimg2" of="$outimg" conv=sparse bs=128K count=$blocks \
> +        seek=$blocks status=none
> +    pos=$((2 * bootsz))
> +fi
> +
> +if [ "$rpmbsz" -gt 0 ]; then
> +    echo "  RPMB partition:           $((rpmbsz / 1024))K"
> +    blocks=$(( rpmbsz / (128 * 1024) ))
> +    dd if="$rpmbimg" of="$outimg" conv=sparse bs=128K count=$blocks \
> +        seek=$(( pos / (128 * 1024) )) status=none
> +    pos=$((pos + rpmbsz))
> +fi
> +
> +if [ "$usersz" -lt 1024 ]; then
> +    echo "  User data:                $usersz bytes"
> +elif [ "$usersz" -lt $((1024 * 1024)) ]; then
> +    echo "  User data:                $(( (usersz + 1023) / 1024 ))K ($usersz)"
> +elif [ "$usersz" -lt $((1024 * 1024 * 1024)) ]; then
> +    echo "  User data:                $(( (usersz + 1048575) / 1048576))M ($usersz)"
> +else
> +    echo "  User data:                $(( (usersz + 1073741823) / 1073741824))G ($usersz)"
> +fi
> +dd if="$userimg" of="$outimg" conv=sparse bs=128K seek=$(( pos / (128 * 1024) )) \
> +    count=$(( (usersz + 128 * 1024 - 1) / (128 * 1024) )) status=none
> +pos=$((pos + usersz))
> +truncate "$outimg" -s $pos
> +
> +echo ""
> +echo "Instantiate via '-device emmc,boot-partition-size=$bootsz,rpmb-partition-size=$rpmbsz,drive=$outimg'"

That did not work for me. I had to provide a drive name, not the image path.
An also create PCIe and SDHCI devices. That is:

-device pcie-root-port,id=pcie-root,bus=pcie.0 \
-device sdhci-pci,bus=pcie-root \
-device emmc,boot-partition-size=$bootsz,rpmb-partition-size=$rpmbsz,drive=mmc0
-drive if=none,id=mmc0,file=$outimg,format=raw"

I applied the patches on top of QEMU 10.1.0 if that matters.

Regards,
-- 
Jerome

On 09.09.25 16:25, Jerome Forissier wrote:
> Hi Jan,
> 
> 
> On 8/24/25 09:18, Jan Kiszka wrote:
>> From: Jan Kiszka <jan.kiszka@siemens.com>
>>
>> As an eMMC block device image may consist of more than just the user
>> data partition, provide a helper script that can compose the image from
>> boot partitions, an RPMB partition and the user data image. The script
>> also does the required size validation and/or rounding.
>>
>> Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
>> ---
>>  scripts/mkemmc.sh | 185 ++++++++++++++++++++++++++++++++++++++++++++++
>>  1 file changed, 185 insertions(+)
>>  create mode 100755 scripts/mkemmc.sh
>>
>> diff --git a/scripts/mkemmc.sh b/scripts/mkemmc.sh
>> new file mode 100755
>> index 0000000000..5d40c2889b
>> --- /dev/null
>> +++ b/scripts/mkemmc.sh
>> @@ -0,0 +1,185 @@
>> +#!/bin/sh -e
>> +#
>> +# Create eMMC block device image from boot, RPMB and user data images
>> +#
>> +# Copyright (c) Siemens, 2025
>> +#
>> +# Authors:
>> +#  Jan Kiszka <jan.kiszka@siemens.com>
>> +#
>> +# This work is licensed under the terms of the GNU GPL version 2.
>> +# See the COPYING file in the top-level directory.
>> +#
>> +
>> +usage() {
>> +    echo "$0 [OPTIONS] USER_IMG[:SIZE] OUTPUT_IMG"
>> +    echo ""
>> +    echo "SIZE must be a power of 2. If no SIZE is specified, the size of USER_ING will"
>> +    echo "be used (rounded up)."
>> +    echo ""
>> +    echo "Supported options:"
>> +    echo "  -b BOOT1_IMG[:SIZE]   Add boot partitions. SIZE must be multiples of 128K. If"
>> +    echo "                          no SIZE is specified, the size of BOOT_IMG will be"
> 
> the size of BOOT1_IMG
> 

Thanks, fixed.

>> +    echo "                          used (rounded up). BOOT1_IMG will be stored in boot"
>> +    echo "                          partition 1, and a boot partition 2 of the same size"
>> +    echo "                          will be created as empty (all zeros) unless -B is"
>> +    echo "                          specified as well."
>> +    echo "  -B BOOT2_IMG          Fill boot partition 2 with BOOT2_IMG. Must be combined"
>> +    echo "                          with -b which is also defining the partition size."
>> +    echo "  -r RPMB_IMG[:SIZE]    Add RPMB partition. SIZE must be multiples of 128K. If"
>> +    echo "                          no SIZE is specified, the size of RPMB_IMG will be"
>> +    echo "                          used (rounded up)."
>> +    echo "  -h, --help            This help"
>> +    echo ""
>> +    echo "All SIZE parameters support the units K, M, G. If SIZE is smaller than the"
>> +    echo "associated image, it will be truncated in the output image."
>> +    exit "$1"
>> +}
>> +
>> +process_size() {
>> +    if [ "${4#*:}" = "$4"  ]; then
>> +        if ! size=$(stat -L -c %s "$2" 2>/dev/null); then
>> +            echo "Missing $1 image '$2'." >&2
>> +            exit 1
>> +        fi
>> +        if [ "$3" = 128 ]; then
>> +            size=$(( (size + 128 * 1024 - 1) & ~(128 * 1024 - 1) ))
>> +        elif [ $(( size & (size - 1) )) -gt 0 ]; then
>> +            n=0
>> +            while [ "$size" -gt 0 ]; do
>> +                size=$((size >> 1))
>> +                n=$((n + 1))
>> +            done
>> +            size=$((1 << n))
>> +        fi
>> +    else
>> +        value="${4#*:}"
>> +        if [ "${value%K}" != "$value" ]; then
>> +            size=${value%K}
>> +            multiplier=1024
>> +        elif [ "${value%M}" != "$value" ]; then
>> +            size=${value%M}
>> +            multiplier=$((1024 * 1024))
>> +        elif [ "${value%G}" != "$value" ]; then
>> +            size=${value%G}
>> +            multiplier=$((1024 * 1024 * 1024))
>> +        else
>> +            size=$value
>> +            multiplier=1
>> +        fi
>> +        if [ "$size" -eq "$size" ] 2>/dev/null; then
>> +            size=$((size * multiplier))
>> +        else
>> +            echo "Invalid value '$value' specified for $2 image size." >&2
>> +            exit 1
>> +        fi
>> +        if [ "$3" = 128 ]; then
>> +            if [ $(( size & (128 * 1024 - 1) )) -ne 0 ]; then
>> +                echo "The $2 image size must be multiples of 128K." >&2
>> +                exit 1
>> +            fi
>> +        elif [ $(( size & (size - 1) )) -gt 0 ]; then
>> +            echo "The %2 image size must be power of 2." >&2
>> +            exit 1
>> +        fi
>> +    fi
>> +    echo $size
>> +}
>> +
>> +userimg=
>> +outimg=
>> +bootimg1=
>> +bootimg2=/dev/zero
>> +bootsz=0
>> +rpmbimg=
>> +rpmbsz=0
>> +
>> +while [ $# -gt 0 ]; do
>> +    case "$1" in
>> +        -b)
>> +            shift
>> +            [ $# -ge 1 ] || usage 1
>> +            bootimg1=${1%%:*}
>> +            bootsz=$(process_size boot "$bootimg1" 128 "$1")
>> +            shift
>> +            ;;
>> +        -B)
>> +            shift
>> +            [ $# -ge 1 ] || usage 1
>> +            bootimg2=$1
>> +            shift
>> +            ;;
>> +        -r)
>> +            shift
>> +            [ $# -ge 1 ] || usage 1
>> +            rpmbimg=${1%%:*}
>> +            rpmbsz=$(process_size RPMB "$rpmbimg" 128 "$1")
>> +            shift
>> +            ;;
>> +        -h|--help)
>> +            usage 0
>> +            ;;
>> +        *)
>> +            if [ -z "$userimg" ]; then
>> +                userimg=${1%%:*}
>> +                usersz=$(process_size user "$userimg" 2 "$1")
>> +            elif [ -z "$outimg" ]; then
>> +                outimg=$1
>> +            else
>> +                usage 1
>> +            fi
>> +            shift
>> +            ;;
>> +    esac
>> +done
>> +
>> +[ -n "$outimg" ] || usage 1
>> +
>> +if [ "$bootsz" -gt $((32640 * 1024)) ]; then
>> +    echo "Boot image size is larger than 32640K." >&2
>> +    exit 1
>> +fi
> 
> Should we warn if BOOT1_IMG and/or BOOT2_IMG are truncated as a result
> of $bootsz being too small? I can see how providing a larger size can be
> useful to be able to later extend the filesystem, but a smaller size is
> more likely to indicate an error I suppose?

Done, will be part of v4.

> 
>> +if [ "$rpmbsz" -gt $((16384 * 1024)) ]; then
>> +    echo "RPMB image size is larger than 16384K." >&2
>> +    exit 1
>> +fi> +
>> +echo "Creating eMMC image"
>> +
>> +truncate "$outimg" -s 0
>> +pos=0
>> +
>> +if [ "$bootsz" -gt 0 ]; then
>> +    echo "  Boot partition 1 and 2:   $((bootsz / 1024))K each"
>> +    blocks=$(( bootsz / (128 * 1024) ))
>> +    dd if="$bootimg1" of="$outimg" conv=sparse bs=128K count=$blocks \
>> +        status=none
>> +    dd if="$bootimg2" of="$outimg" conv=sparse bs=128K count=$blocks \
>> +        seek=$blocks status=none
>> +    pos=$((2 * bootsz))
>> +fi
>> +
>> +if [ "$rpmbsz" -gt 0 ]; then
>> +    echo "  RPMB partition:           $((rpmbsz / 1024))K"
>> +    blocks=$(( rpmbsz / (128 * 1024) ))
>> +    dd if="$rpmbimg" of="$outimg" conv=sparse bs=128K count=$blocks \
>> +        seek=$(( pos / (128 * 1024) )) status=none
>> +    pos=$((pos + rpmbsz))
>> +fi
>> +
>> +if [ "$usersz" -lt 1024 ]; then
>> +    echo "  User data:                $usersz bytes"
>> +elif [ "$usersz" -lt $((1024 * 1024)) ]; then
>> +    echo "  User data:                $(( (usersz + 1023) / 1024 ))K ($usersz)"
>> +elif [ "$usersz" -lt $((1024 * 1024 * 1024)) ]; then
>> +    echo "  User data:                $(( (usersz + 1048575) / 1048576))M ($usersz)"
>> +else
>> +    echo "  User data:                $(( (usersz + 1073741823) / 1073741824))G ($usersz)"
>> +fi
>> +dd if="$userimg" of="$outimg" conv=sparse bs=128K seek=$(( pos / (128 * 1024) )) \
>> +    count=$(( (usersz + 128 * 1024 - 1) / (128 * 1024) )) status=none
>> +pos=$((pos + usersz))
>> +truncate "$outimg" -s $pos
>> +
>> +echo ""
>> +echo "Instantiate via '-device emmc,boot-partition-size=$bootsz,rpmb-partition-size=$rpmbsz,drive=$outimg'"
> 
> That did not work for me. I had to provide a drive name, not the image path.

Yeah, I already fixed that in v3.

> An also create PCIe and SDHCI devices. That is:
> 
> -device pcie-root-port,id=pcie-root,bus=pcie.0 \
> -device sdhci-pci,bus=pcie-root \

At least for the virt machine, just "-device sdhci-pci" is enough.

> -device emmc,boot-partition-size=$bootsz,rpmb-partition-size=$rpmbsz,drive=mmc0
> -drive if=none,id=mmc0,file=$outimg,format=raw"
> 
> I applied the patches on top of QEMU 10.1.0 if that matters.
> 
> Regards,

Thanks for review and testing!

Jan

-- 
Siemens AG, Foundational Technologies
Linux Expert Center

On 24/8/25 09:18, Jan Kiszka wrote:
> From: Jan Kiszka <jan.kiszka@siemens.com>
> 
> As an eMMC block device image may consist of more than just the user
> data partition, provide a helper script that can compose the image from
> boot partitions, an RPMB partition and the user data image. The script
> also does the required size validation and/or rounding.
> 
> Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
> ---
>   scripts/mkemmc.sh | 185 ++++++++++++++++++++++++++++++++++++++++++++++
>   1 file changed, 185 insertions(+)
>   create mode 100755 scripts/mkemmc.sh
> 
> diff --git a/scripts/mkemmc.sh b/scripts/mkemmc.sh
> new file mode 100755
> index 0000000000..5d40c2889b
> --- /dev/null
> +++ b/scripts/mkemmc.sh
> @@ -0,0 +1,185 @@
> +#!/bin/sh -e
> +#
> +# Create eMMC block device image from boot, RPMB and user data images
> +#
> +# Copyright (c) Siemens, 2025
> +#
> +# Authors:
> +#  Jan Kiszka <jan.kiszka@siemens.com>
> +#
> +# This work is licensed under the terms of the GNU GPL version 2.
> +# See the COPYING file in the top-level directory.

We now require SPDX tags, otherwise LGTM!