Windows Update frozen bootloop, can't remove update using DISM

• OS: Windows 10 Pro x64 14393.187
• PC: Asus M51AC-FR034S
• Hardware: Intel Core i7 4770S; Asus GTX 760; 16GB DDR3 1333MHz
• Storage: 1TB HDD; 240GB SSD (Samsung 850 Evo)

After 35 days of uptime, fearing what would happen if I rebooted my computer (I've got problems with WU in the past), I decided to give Windows Update a try and finally install those updates (can't remember which KB) it has been trying to install for 3 months. I rebooted my computer, and then it was showing "Rebooting..." and then the screen froze. So I rebooted the PC, it showed "Installing updates..." and then it froze. I rebooted it again, and then it showed "Couldn't install updates. Undoing changes..." and then it froze. Same when booting in Safe Mode. So I tried launching a repair command prompt from the PE environment, to list the installed updates using dism /image:d:\windows /get-packages and I got this:

Identité du package : Package_for_RollupFix~31bf3856ad364e35~amd64~~14393.953.1.2
État : Installation en attente
Type de version : Security Update
Heure d’installation : 26/03/2017 13:48

L’opération a réussi.

("Installation en attente" meaning "Installation pending")

So I ran dism /image:d:\windows /remove-package /packagename:[longname]:

Traitement de 1 sur 1 - Suppression du package Package_for_RollupFix~31bf3856ad364e35~amd64~~14393.953.1.2
[==========================100.0%==========================]
Une erreur s’est produite - Package_for_RollupFix Erreur : 0x80070bc9

Erreur : 3017

Échec de l’opération demandée. Il est nécessaire de redémarrer le système pour restaurer les modifications apportées.

Le fichier journal DISM se trouve à l’emplacement X:\windows\Logs\DISM\dism.log

• Is it possible to remove that update?
  • If DISM really can't work, is it possible to remove it manually (remove some files, change some registry values) ?
• Preferrably without reinstalling Windows?

EDIT: Here is the DISM.log file (the relevant errors are near lines 2232 and 2312).

EDIT 2: dism [...] /scanhealth did not find any errors.

EDIT 3: When I try to boot into Windows, it shows the "undoing changes" screen, and then the system freezes - screen is frozen, mouse pointer is not visible, num/caps/scroll lock is unresponsive, and I don't have any HDD activity LED. Also, I tried letting the PC work over night (maybe it would un-freeze automagically at some time), but after 19 hours it hasn't changed.

EDIT 4: Following Ramhound's advice, I tried to uninstall previous updates (the 14393.*** ones) but I noticed that DISM is always stuck at 10.0% and simply stays there, while writing to its log file:

2017-03-27 19:08:34, Error                 CSI    00001800 (F) Current pending rollback transaction content precludes other operations; reboot to complete rollback.[gle=0x80004005]
2017-03-27 19:08:34, Error                 CSI    00001801 (F) HRESULT_FROM_WIN32(ERROR_FAIL_REBOOT_REQUIRED) #13918885# from Windows::COM::CComponentStore::InternalTransact(...)[gle=0x80070bc9]
2017-03-27 19:08:34, Error                 CSI    00001802@2017/3/27:17:08:34.745 (F) onecore\base\wcp\componentstore\com\store.cpp(4970): Error HRESULT_FROM_WIN32(ERROR_FAIL_REBOOT_REQUIRED) originated in function Windows::COM::CComponentStore::InternalTransact expression: HRESULT_FROM_WIN32(3017L)
[gle=0x80004005]
2017-03-27 19:08:34, Info                  CBS    Added X:\windows\Logs\DISM\dism.log to WER report.
2017-03-27 19:08:34, Info                  CBS    Failed to create filter driver list file. [HRESULT = 0x80070003 - ERROR_PATH_NOT_FOUND]
2017-03-27 19:08:34, Info                  CBS    Failed to submit the Windows Error Report. [HRESULT = 0x8007053d - ERROR_SERVER_DISABLED]
2017-03-27 19:08:34, Error                 CSI    00001803 (F) HRESULT_FROM_WIN32(ERROR_FAIL_REBOOT_REQUIRED) #13918883# from Windows::ServicingAPI::CCSITransaction::ICSITransaction2_Analyze(Flags = 0, riid = {f4d9decb-0250-4ad4-9500-85c7f2f281ec}, ppUnk = NULL, disp = 0)[gle=0x80070bc9]
2017-03-27 19:08:34, Info                  CBS    Failed to get transaction analysis. [HRESULT = 0x80070bc9 - ERROR_FAIL_REBOOT_REQUIRED]
2017-03-27 19:08:34, Info                  CBS    Failed to get inventory. [HRESULT = 0x80070bc9 - ERROR_FAIL_REBOOT_REQUIRED]
2017-03-27 19:08:34, Info                  CSI    00001804@2017/3/27:17:08:34.747 CSI Transaction @0xd7d0d80 destroyed
2017-03-27 19:08:34, Info                  CBS    Failed to get CSI Inventory [HRESULT = 0x80070bc9 - ERROR_FAIL_REBOOT_REQUIRED]
2017-03-27 19:08:34, Info                  CBS    Failed to get component state. [HRESULT = 0x80070bc9 - ERROR_FAIL_REBOOT_REQUIRED]
2017-03-27 19:08:34, Info                  CBS    Plan: Package: Package_1378_for_KB3213986~31bf3856ad364e35~amd64~~10.0.1.1, Update: 3213986-2798_neutral, current: Absent, pending: Default, start: Absent, applicable: Absent, targeted: Absent, limit: Absent, selected: Default
2017-03-27 19:08:34, Info                  CBS    Plan: Force applicability state to absent due to absent limit state on package: Package_1379_for_KB3213986~31bf3856ad364e35~amd64~~10.0.1.1
2017-03-27 19:08:34, Info                  CBS    Plan: Package: Package_1379_for_KB3213986~31bf3856ad364e35~amd64~~10.0.1.1, current: Staged, pending: Default, start: Staged, applicable: Absent, targeted: Absent, limit: Absent
2017-03-27 19:08:34, Info                  CSI    00001805 Transaction merge required, do-not-merge flag passed.
2017-03-27 19:08:34, Info                  CSI    00001806@2017/3/27:17:08:34.750 CSI Transaction @0xadf26b0 initialized for deployment engine {d16d444c-56d8-11d5-882d-0080c847b195} with flags 00000002 and client id 'TI5.3364_3202296:879/'

Every 2 or 3 seconds (here it's 19:08:34, the previous one was 31 and the next one 36), and it keeps writing the same thing over and over.

EDIT 5: I removed C:\Windows\WinSxS\pending.xml and now it got to the lock screen! Well, actually, it got to the lock screen but it stayed there. I think I fixed the update problem, but not the freeze problem. I took my stopwatch, and it seems the system freezes 5 seconds (+ or - 1 second) after the boot screen disappears, no matter if in Safe Mode (which, by the way, stays on a black screen). Before I deleted the file, Windows was freezing on an update screen, now it's freezing on the login screen. I restarted multiple times, sometimes I'm fast enough to press a key and hide the lock screen, but not fast enough to type my password and log in, before it freezes.

EDIT 6: When booting into "Safe Mode with Networking" (the normal Safe Mode boots directly to normal), I managed to get a BSOD with the error WHEA_UNCORRECTABLE_ERROR. Unfortunately, after 30 minutes, it was still at 0%, and as usual, it didn't create a dump file.

I finally solved my problem!

The solution was completely unrelated to anything I've said previously!

I simply copied everything in the C:\Windows\system32\config\RegBack folder (which was created automatically before the update) to C:\Windows\system32\config, and everything worked correctly.

If I have the time, I will try to compare the two registry hives to see what changed.