Vero 4k+: not getting gigabit link speed, only 100Mbit/s

My issue is that the Vero 4K+ is not negotiating a gigabit connection to my switch. I have tried different ethernet cables and two different gigabit switches:

  • Ubiquiti UniFi US-8-150W (managed, port link negotiation set to auto)
  • HP ProCurve 1400-8G (unmanaged)

I also tested the kernel from ([TESTING] Vero 4K / 4K + video improvements), no changes.

Here are the logs:
https://paste.osmc.tv/mojepoxoqe

Here’s the output of ethtool (with UniFi switch):

osmc@osmc:~$ sudo ethtool eth0
Settings for eth0:
Supported ports: [ TP MII ]
Supported link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
1000baseT/Half 1000baseT/Full
Supported pause frame use: Symmetric Receive-only
Supports auto-negotiation: Yes
Advertised link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
1000baseT/Half 1000baseT/Full
Advertised pause frame use: Symmetric Receive-only
Advertised auto-negotiation: Yes
Link partner advertised link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
Link partner advertised pause frame use: No
Link partner advertised auto-negotiation: Yes
Speed: 100Mb/s
Duplex: Full
Port: MII
PHYAD: 0
Transceiver: external
Auto-negotiation: on
Supports Wake-on: ug
Wake-on: d
Current message level: 0x0000003d (61)
drv link timer ifdown ifup
Link detected: yes

Any suggestions?