hi - I've got a R500 as my primary AP, with the R310 as secondary. If I change the R310 as the primary AP, will the R500 work in meshed mode (i.e. no ethernet cable)?
The R310 cannot be involved in meshing, either as root or mesh. If you had two R500s, they could connect to each other, but the R310 cannot connect to another AP or have another AP connect to it.