Support for eMMC hardware boot partition /dev/mmcblk0boot0

General Discussions
1

For devices that stores uboot in eMMC hardware boot partition like /dev/mmcblk0boot0 or /dev/mmcblk0boot1, is there a way to configure mender-convert to support these hardware partitions.

Looks like mender-convert always creates a logical partition /dev/mmcblk0p1 for uboot even if it’s not required or maybe I couldn’t find an option to disable creation of this partition. Can someone help me with this.

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Thanks,

John

2

Hi @john.kuriakose,

Thanks for reaching out!
To my understanding, those *boot0, *boot1 partitions are not real partitions, but actually reserved areas in the (usually) eMMC where the first stage loader needs to be put. So it’s not really a question of partitioning, more of data layout.
There is a way to do this from a config file, essentially you modify the image once mender-convert has taken care of the Linux payload. An example is here: mender-convert/configs/rockpro64_config at 1a58bb559dc5be4ba0a937cf4b3b29047ed2d0c1 · mendersoftware/mender-convert · GitHub

Greetz,
Josef

3

Hi @TheYoctoJester , Thanks for your quick reply.

I wanted to know how to configure mender-convert not to create the boot partition which is mounted at /uboot.

In my understanding *boot0, *boot1 are considered as actual hardware partitions implemented on the eMMC, not as logical partitions created in the user data area of eMMC. In our case signed uboot is flashed directly to *boot0 or *boot1 hardware partition at factory and hence we don’t need the boot partition which is the first logical partition mender-convert creates. We will need only partitions for rootfsA, rootfsB and data.

Even if I specify the size of boot partition size MENDER_BOOT_PART_SIZE_MB as zero it still creates the partition with default size.

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Thanks,

John

4

Hi John,

In a nutshell, thats just not possible given the current state of the scripts as far as I can tell. Feel free to implement and send a PR to improve this, or reach out for professional services if this is a crucial feature addition for you.

Greetz,
Josef

5

Hi Josef,

I will see if I can make the changes and create a PR. Thanks again for your support.

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John