So now I think my problem is clearly the result of my Asus X99 motherboard.
I was researching the components of my new PC and discovered a lot of anecdotal complaints about boot failure during Post that seemed related to USB. I'm providing some of the links I discovered below in case anyone other than the few here who have mentioned that they have an ASUS motherboard. Based on a comment on the last youtube video here, I disabled a lot of functions in the BIOS that related to the handoff to the OS. I am now able to boot and use my devices normally. - https://www.youtube.com/watch?v=_av2DUQDE1A - https://www.youtube.com/watch?v=cK23Jt6KJXs - https://rog.asus.com/forum/showthread.php?78607-Asus-Confirmed-yesterday-that-X99-boards-has-boot-issues-with-Usb-Hubs-connected - https://www.youtube.com/watch?v=A6SOdSeWSCM - https://www.youtube.com/watch?v=2MDYUBp-1i4 - https://www.youtube.com/watch?v=A6SOdSeWSCM * See comment from Alexandre Esquenet, how provides a solution here: http://users.skynet.be/xixou/x99_usb_boot_issue.png -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1437492 Title: boot stalls on USB detection errors Status in linux package in Ubuntu: Confirmed Status in linux package in Debian: New Bug description: My system boots slow. I investigated this and it seems systemd-udev-settle.service is the culprit. My system runs ext4 with GPT on UEFI. I do not use encryption or LVM. $ journalctl -u systemd-udev-settle -- Logs begin at fri 2015-03-27 19:03:06 CET, end at fri 2015-03-27 22:06:32 CET. -- mar 27 19:03:42 hostname systemd[1]: Started udev Wait for Complete Device Initialization. $ systemd-analyze Startup finished in 14.865s (firmware) + 11.133s (loader) + 6.127s (kernel) + 42.079s (userspace) = 1min 14.206s $ systemd-analyze critical-chain http://paste.ubuntu.com/10691416/ $ systemd-analyze blame 36.013s systemd-udev-settle.service http://paste.ubuntu.com/10691314/ $ systemctl show systemd-udev-settle.service -p RequiredBy RequiredBy= $ systemctl show systemd-udev-settle.service -p WantedBy WantedBy=friendly-recovery.service $ systemd-analyze plot > boot.svg http://imgh.us/boot_1.svg $ systemd-analyze dump http://paste.ubuntu.com/10691856/ ProblemType: Bug DistroRelease: Ubuntu 15.04 Package: systemd 219-5ubuntu1 ProcVersionSignature: Ubuntu 3.19.0-10.10-generic 3.19.2 Uname: Linux 3.19.0-10-generic x86_64 ApportVersion: 2.16.2-0ubuntu5 Architecture: amd64 CurrentDesktop: GNOME-Flashback:Unity Date: Fri Mar 27 22:05:28 2015 InstallationDate: Installed on 2013-12-26 (455 days ago) InstallationMedia: Ubuntu 13.10 "Saucy Salamander" - Release amd64 (20131016.1) MachineType: ASUS All Series ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.19.0-10-generic.efi.signed root=UUID=31dc4488-28d4-4d2a-aa51-6733e237d5f8 ro quiet splash vt.handoff=7 SourcePackage: systemd UpgradeStatus: No upgrade log present (probably fresh install) dmi.bios.date: 08/18/2014 dmi.bios.vendor: American Megatrends Inc. dmi.bios.version: 2103 dmi.board.asset.tag: To be filled by O.E.M. dmi.board.name: Z87-PRO dmi.board.vendor: ASUSTeK COMPUTER INC. dmi.board.version: Rev 1.xx dmi.chassis.asset.tag: Asset-1234567890 dmi.chassis.type: 3 dmi.chassis.vendor: Chassis Manufacture dmi.chassis.version: Chassis Version dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvr2103:bd08/18/2014:svnASUS:pnAllSeries:pvrSystemVersion:rvnASUSTeKCOMPUTERINC.:rnZ87-PRO:rvrRev1.xx:cvnChassisManufacture:ct3:cvrChassisVersion: dmi.product.name: All Series dmi.product.version: System Version dmi.sys.vendor: ASUS To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1437492/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp