Upgrade from 1607 to 1703, error 0xc1900104

I read online it could indicate that the System Reserved partition ran out of space.

Checking the file "C:\$WINDOWS.~BT\Sources\Panther\setupact.log" I found this line:

2017-07-29 20:04:54, Info CONX CFreeSystemPartitionDiskSpaceChecker: checked InsufficientSystemPartitionDiskSpace, found HardBlock.Not enough space on partition [\\?\GLOBALROOT\Device\HarddiskVolume3\] Required: 15 MB. Available: 10 MB

Here it is the output of diskpart.exe

Microsoft Windows [Version 10.0.14393]
(c) 2016 Microsoft Corporation. All rights reserved.


C:\Windows\system32>diskpart


Microsoft DiskPart version 10.0.14393.0


Copyright (C) 1999-2013 Microsoft Corporation.
On computer: DESKTOP-JRLS3OQ


DISKPART> select disk 1


Disk 1 is now the selected disk.


DISKPART> list partition


Partition ### Type Size Offset
------------- ---------------- ------- -------
Partition 1 Recovery 450 MB 1024 KB
Partition 2 System 100 MB 451 MB
Partition 3 Reserved 16 MB 551 MB
Partition 4 Primary 157 GB 677 MB
Partition 5 Recovery 74 GB 158 GB


DISKPART> select partition 3


Partition 3 is now the selected partition.


DISKPART> detail partition


Partition 3
Type : e3c9e316-0b5c-4db8-817d-f92df00215ae
Hidden : Yes
Required: No
Attrib : 0X8000000000000000
Offset in Bytes: 577765376


There is no volume associated with this partition.


DISKPART> list volume


Volume ### Ltr Label Fs Type Size Status Info
---------- --- ----------- ----- ---------- ------- --------- --------
Volume 0 E DVD-ROM 0 B No Media
Volume 1 D Data 2 NTFS Partition 931 GB Healthy
Volume 2 C NTFS Partition 157 GB Healthy Boot
Volume 3 Recovery NTFS Partition 450 MB Healthy Hidden
Volume 4 FAT32 Partition 100 MB Healthy System
Volume 5 RAW Partition 74 GB Healthy Hidden
Volume 6 F Data NTFS Partition 931 GB Healthy


DISKPART> select volume 2


Volume 2 is the selected volume.


DISKPART> detail volume


Disk ### Status Size Free Dyn Gpt
-------- ------------- ------- ------- --- ---
* Disk 1 Online 232 GB 110 MB *


Read-only : No
Hidden : No
No Default Drive Letter: No
Shadow Copy : No
Offline : No
BitLocker Encrypted : No
Installable : Yes


Volume Capacity : 157 GB
Volume Free Space : 83 GB

Here it is a screenshot of diskmgmt.msc


I managed to free ~100 MB, now it's marked as raw (unallocated space) and it is next to the SRP.
I wish I could merge this space with the SRP but I don't know how to.
As you can see the diskmgmt utility doesn't recognise the SRP while the diskpart program does (it's the 16MB partition marked as hidden, number 3).
What should I do?
Note: I can use Linux utilities but I would like to use Windows ones first if avaiable, I don't want to mess with my installations.
Note: I am currently dual booting with Arch Linux using GRUB on the EFI partition. Arch Linux is installed on Volume 5 (I don't know why is marked as hidden and raw from diskpart and as recovery partition from diskmgmt).

The file system of the partition is unknown on linux and Windows set it as "other", I didn't find any program that is able to expand it.

I upgraded succesfully without touching the SRP, I followed the article in this thread.