STP blocking uplink port, correct way to avoid?

Gear: HPE Aruba 2530G 52-ports switch.

Config: Uplink is port 52, as those last four ports are SFP-ports. A colleague managed to patch up a cable from port 4 AND port 14 as well to the upstream switch - making two "loops".

Problem: The Aruba figured it would block port 14 and 52! That's maybe fair enough, but only port 52 has all the VLANs, which practically took down the whole switch, as port 4 now being root port only had an untagged vlan..

Question: What's the correct to avoid this and make the STP keep 52 as root port if another loop occurs? (Port priority, root guard, bpdu guard/filter etc)

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BTWs: I tried "span 52 prio 4", this had NO effect to my surprise! But this is maybe not the correct way to do it? Docs says per-port priority doesn't work for RSTP, seems that MSTP is multiple RSTP too.. But the fact that is selects a root port that doesn't even have more than 1 untagged vlan seems odd to me, but I'm not really into the different STP protocols.

Example from CLI, edited to match what I saw on console:

 Multiple Spanning Tree (MST) Information Did try some googling, but wonder what is the best practic method to solve this. Force Version : MSTP-operation IST Mapped VLANs : 1-4094 Switch MAC Address : 08f1ea-28d580 Switch Priority : 32768 Max Age : 20 Max Hops : 20 Forward Delay : 15 Topology Change Count : 21 Time Since Last Change : 41 mins CST Root MAC Address : 2c59e5-8c8d20 CST Root Priority : 16384 CST Root Path Cost : 40000 CST Root Port : 52 IST Regional Root MAC Address : 08f1ea-28d580 IST Regional Root Priority : 32768 IST Regional Root Path Cost : 0 IST Remaining Hops : 20 Root Guard Ports : Loop Guard Ports : TCN Guard Ports : BPDU Protected Ports : BPDU Filtered Ports : PVST Protected Ports : PVST Filtered Ports : Root Inconsistent Ports : Loop Inconsistent Ports : | Prio | Designated Hello Port Type | Cost rity State | Bridge Time PtP Edge ----- ---------- + --------- ---- ------------ + ------------- ---- --- ---- 1 100/1000T | 20000 128 Forwarding | 08f1ea-28d580 2 Yes Yes 2 100/1000T | 20000 128 Forwarding | 08f1ea-28d580 2 Yes Yes 3 100/1000T | Auto 128 Disabled | 2 Yes No 4 100/1000T | 20000 128 Forwarding | 6cc217-9b99e0 2 Yes No <- 5 100/1000T | Auto 128 Disabled | 2 Yes No 6 100/1000T | Auto 128 Disabled | 2 Yes No 7 100/1000T | Auto 128 Disabled | 2 Yes No 8 100/1000T | Auto 128 Disabled | 2 Yes No 9 100/1000T | Auto 128 Disabled | 2 Yes No 10 100/1000T | Auto 128 Disabled | 2 Yes No 11 100/1000T | Auto 128 Disabled | 2 Yes No 12 100/1000T | Auto 128 Disabled | 2 Yes No 13 100/1000T | Auto 128 Disabled | 2 Yes No 14 100/1000T | 20000 128 Blocking | 2 Yes No <- 15 100/1000T | Auto 128 Disabled | 2 Yes No 16 100/1000T | Auto 128 Disabled | 2 Yes No 17 100/1000T | Auto 128 Disabled | 2 Yes No 18 100/1000T | Auto 128 Disabled | 2 Yes No 19 100/1000T | 200000 128 Forwarding | 08f1ea-28d580 2 Yes Yes 20 100/1000T | 20000 128 Forwarding | 08f1ea-28d580 2 Yes Yes 21 100/1000T | Auto 128 Disabled | 2 Yes No 22 100/1000T | Auto 128 Disabled | 2 Yes No 23 100/1000T | Auto 128 Disabled | 2 Yes No 24 100/1000T | Auto 128 Disabled | 2 Yes No 25 100/1000T | Auto 128 Disabled | 2 Yes No 26 100/1000T | Auto 128 Disabled | 2 Yes No 27 100/1000T | Auto 128 Disabled | 2 Yes No 28 100/1000T | 20000 128 Forwarding | 08f1ea-28d580 2 Yes Yes 29 100/1000T | Auto 128 Disabled | 2 Yes No 30 100/1000T | Auto 128 Disabled | 2 Yes No 31 100/1000T | Auto 128 Disabled | 2 Yes No 32 100/1000T | Auto 128 Disabled | 2 Yes No 33 100/1000T | Auto 128 Disabled | 2 Yes No 34 100/1000T | Auto 128 Disabled | 2 Yes No 35 100/1000T | Auto 128 Disabled | 2 Yes No 36 100/1000T | 20000 128 Forwarding | 08f1ea-28d580 2 Yes Yes 37 100/1000T | 20000 128 Forwarding | 08f1ea-28d580 2 Yes Yes 38 100/1000T | Auto 128 Disabled | 2 Yes No 39 100/1000T | 2000000 128 Forwarding | 08f1ea-28d580 2 Yes Yes 40 100/1000T | Auto 128 Disabled | 2 Yes No 41 100/1000T | Auto 128 Disabled | 2 Yes No 42 100/1000T | 20000 128 Forwarding | 08f1ea-28d580 2 Yes Yes 43 100/1000T | Auto 128 Disabled | 2 Yes No 44 100/1000T | Auto 128 Disabled | 2 Yes No 45 100/1000T | Auto 128 Disabled | 2 Yes No 46 100/1000T | 20000 128 Forwarding | 08f1ea-28d580 2 Yes Yes 47 100/1000T | 20000 128 Forwarding | 08f1ea-28d580 2 Yes Yes 48 100/1000T | 20000 128 Forwarding | 08f1ea-28d580 2 Yes Yes 49 | Auto 128 Disabled | 2 Yes No 50 | Auto 128 Disabled | 2 Yes No 51 | Auto 128 Disabled | 2 Yes No 52 1000LX | 20000 64 Blocking | 2 Yes No <- 

Did try some googling, but wonder what is the best practice method to solve this.