Trying to see how things perform when we don't fix the GPT as suggested:
# parted /dev/mmcblk0 mkpart persist 2048 2058
Warning: Not all of the space available to /dev/mmcblk0 appears to be used, you can fix the GPT to use all of the space (an extra 25661440 blocks) or continue with the current setting?
parted: invalid token: persist
Fix/Ignore? i
Partition name? []?
File system type? [ext2]?
Start? ^C
Note that hitting ^C on the "fix/ignore" or "partition name" prompts have no effect, one cannot abort before the "file system type" prompt.
Then once I have accepted the fix things do work as expected:
# parted /dev/mmcblk0 mkpart persist 2048 2058
Information: You may need to update /etc/fstab.