I was able to work around the bug by:
dd if=/dev/zero of=/dev/sdXN
(... where /dev/sdXN is the appropriate device on my system.)
I used two partitions: one for / (root), and the other for /boot
It was the /boot partition that Ubiquity would resize.
Ubiquity would shrink it from 500 MiB to slightly less, perhaps around 499.7 MiB.
It may be that Ubiquity is shrinking from 500MiB to 524MB. Ubiquity may display and analyze partitions in MB (base 10), not MiB (base 2).
It is interesting that:
1) the shrink only seems to happen if the partition is formatted prior to Ubiquity running.
In other words:
2) I believe the (unwanted) shrink dose not happen if the partition is filled with zeros. (Actually, it is possible that only the beginning of the partition needs to be zeroed.)
I encountered this bug installing 18.04.
I was able to work around the bug by:
dd if=/dev/zero of=/dev/sdXN
(... where /dev/sdXN is the appropriate device on my system.)
I used two partitions: one for / (root), and the other for /boot
It was the /boot partition that Ubiquity would resize.
Ubiquity would shrink it from 500 MiB to slightly less, perhaps around 499.7 MiB.
It may be that Ubiquity is shrinking from 500MiB to 524MB. Ubiquity may display and analyze partitions in MB (base 10), not MiB (base 2).
It is interesting that:
1) the shrink only seems to happen if the partition is formatted prior to Ubiquity running.
In other words:
2) I believe the (unwanted) shrink dose not happen if the partition is filled with zeros. (Actually, it is possible that only the beginning of the partition needs to be zeroed.)