HFS+ disks are mounted automatically, but read-only by default. To remount them read-write:

mount | grep 'type hfsplus (ro' | while read disk line; do echo "$disk $line"; echo "Remounting $disk read-write:"; sudo mount -o remount,rw,force $disk && echo OK; done

Once mounted read-write, it still needs sudo to be writable, since Mac disk have different user IDs. Would this work to make it writable by current user without sudo ?

sudo chown -c $(id -u) /run/media/andromeda/*

Sometimes it fails, even if it said OK. mount | grep 'type hfsplus (ro' will still show the disk mounted as "ro". And dmesg | tail will show something like

[1906660.136270] hfsplus: filesystem was not cleanly unmounted, running fsck.hfsplus is recommended.  leaving read-only.

Trying fsck.hfsplus may not work:

sudo fsck.hfsplus -p -f /dev/sdg2
   Executing fsck_hfs (version 540.1-Linux).
fsck_hfs: Volume is journaled.  No checking performed.
fsck_hfs: Use the -f option to force checking.