Supported device with different flash IC

TL;DR: Please point me in the direction of where to configure the model of flash IC to build OpenWRT for an otherwise already supported device.

Hi all, I'm not new to embedded dev but I'm new to OpenWRT. I've bought a supported device, but just my luck, it has a different flash IC than the supported device. Is there any chance of some guidance as to how to get OpenWRT working on this thing?

To save you going through my previous thread, the issue is that OpenWRT appears to install OK, the device appears to boot, but the network IFs never transmit any data, only the autonegotiation ever completes (which I would expect is the PHY in action and not the interface, so I guess the IF is dead). With some help from one of the original devs of this device's support, I've come to realise that the device is built for an MX25L6405D and actually contains an MX25L6406E, and that's a likely reason why OpenWRT isn't working.

I initially suspected I'd need to arrange the partitions differently but the two IC's turn out to be compatible in that regard. I've some idea of the differences between the IC's (mostly timing and a few commands) and I have gathered that the build scripts make use of the DTS(i) files to control the kernel build. Existing devices supporting this IC, such as this one on the same ramips platform have very similar configuration to the existing non-working dts. The only significant difference I see (beyond the partition layout which is correct for my device) is the clock rate, and I can find other devices with this IC which have the same clock rate as the original. This leads me to suspect that the issue comes down to the usage of some of the IO commands which are not supported on the new IC... . But I'm at a loss to find where the protocol of the flash is configured?

The device is being considered by its owner (not me, it's for family) as a write-off and essentially, I'm now interested in getting this thing working because it is by a large margin the cheapest 802.11ac AP/router available (at least, here in AU) and I think it would be a nice public service to get it going. I've got the router open, warranty is void, I've got a meter and serial interface (teensy 4) ready, I'm ready to read lots of docs (into the hundreds of tabs open right now) and I don't expect to be hand-held... I'd just really appreciate some pointers in the right direction so I don't have to reverse engineer OpenWRT just to do the neighbourhood a favour :wink:

Thanks in advance for any advice!