resize hfs+ fails (current xenial mini.iso)

[gregrwm]

i downloaded current xenial mini.iso midday today (jan28) onto a powerbook g4, booted via yaboot, selected manual partitioning, requested shrinking the main hfs+ partition from 30gb to 19gb, it took about 9 hours, then got stuck starting up the partitioner with the progress bar at 50%, stayed thus about 2 hours, whereupon i rebooted, selected manual partitioning, and saw the main hfs+ partition apparently unchanged, still 30gb in size. then booted macos, noticed that startup took far longer than usual, i presume due to running filesystem check. macos concurs main volume size unchanged (27.94gb according to macos). subsequent macos startups now quicker than the prior norm, i presume the end result was no resize but a consolation prize of a defrag.

ProblemType: Bug
DistroRelease: Ubuntu 15.04
Package: debian-installer (not installed)
ProcVersionSignature: Ubuntu 3.19.0-20.20-lowlatency 3.19.8
Uname: Linux 3.19.0-20-lowlatency i686
ApportVersion: 2.17.2-0ubuntu1.1
Architecture: i386
Date: Thu Jan 28 22:53:41 2016
InstallationDate: Installed on 2015-03-30 (304 days ago)
InstallationMedia: Ubuntu-Studio 15.04 "Vivid Vervet" - Beta i386 (20150326)
MemoryUsage:
 total used free shared buffers cached
 Mem: 2062216 1838868 223348 14144 198688 644744
 -/+ buffers/cache: 995436 1066780
 Swap: 2969712 6304 2963408
ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz ro root=UUID=960c92bd-69d3-415f-93b6-2242187e3557 panic=30
SourcePackage: debian-installer
UdevLog: Error: [Errno 2] No such file or directory: '/var/log/udev'
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 01/09/2008
dmi.bios.vendor: Phoenix Technologies, LTD
dmi.bios.version: 6.00 PG
dmi.board.name: K8M800-8237
dmi.chassis.type: 3
dmi.modalias: dmi:bvnPhoenixTechnologies,LTD:bvr6.00PG:bd01/09/2008:svn:pn:pvr:rvn:rnK8M800-8237:rvr:cvn:ct3:cvr:

[gregrwm (gregrwm)]

downloaded xenial-alternate-powerpc.iso on 2016-02-16 at 9:34 CST, burned to dvd, booted from dvd, requested hfs+ resize from 30gb to 21gb, resize spent ~2 hours, then got stuck "Starting up the partitioner...52%", in other words just the same as OP