[Merge] ~xypron/livecd-rootfs:risc-v-grub into livecd-rootfs:ubuntu/master

[Łukasz Zemczak]

Review: Approve

Looking good + I also appreciate the CPC team reviewing this (as we did break riscv64 cloud images once before).
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https://code.launchpad.net/~xypron/livecd-rootfs/+git/livecd-rootfs/+merge/432964
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