Temporary 5th 3.5" drive in TrueNAS Mini E for upgrading?

[Redcoat]

The shenanigans of the C3558D4I-4L are discussed here,

@Etorix , thank you for posting that - I knew I'd seen something on the topic but I could not find it. Before I made my "get the asrock manual" recommendation above I tried to find out which motherboard was in the E, but could not get a fix on that either. I guess my Google-fu is wearing out...

 

[Etorix]

My Google-fu failed as well to find a C3338 mobo at AsRockRack (and the red SATADOM port does look like AsRockRack).
Could it be a custom C3338 motherboard for iXSystems?

 

[Redcoat]

@JetForMe , to assist in sating our curiosity, can we ask you to post whatever ID info you can find on your motherboard so that we have something tp work with.

When I bought a V2 Mini from iXsystems a few years ago I was surprised to receive only a sort of stripped-down quick-reference guide and so went to asrock rack and picked up the board's manual and the IPMI docs, without which I would have been lost on self-help. So I am in sympathy with you right now.

 

[Etorix]

More Google-fu returns reference C3338D2I-4L, page S-29 of the 2020 AsRockRack catalogue, and a picture from an out-of-stock retailer which matches with OP. But no user manual—it's not in the shared manual for the C3758 and C3558 siblings.
Config 3 already disables the PCIe slot, so it's not clear what Config 4 could do but trying should be harmless (and reversible!). If this does not enable SATA ports 3 and 4, then the best solution would be to use ports 1 and 2 (SSDs) while resilvering, two drives at a time.