RP3 x IC880a gateway stopped working

Unless the gateway is on cellular backhaul, you could consider remote logging…

Alternatively (not sure if this has been already mentioned) there are scripts like Log2Ram which will first log to tmpfs and than synch to disk periodically, limiting the number of writes.

(You need to ensure that the packet forwarder log also go to system logs)

Edit – apologies for the noise, just see that we now have a separate topic on that