It seems there is not much support for the Realtek family, and the new RTL8881AM even less.
According to these pages
Arch is Lexra RLX5281 (make menuconfig doesn't have this arch it seems)
Bought a Buffalo WMR-433
Would love to install openwrt on this router ; worked on the WMR-300 (contributed to the page to get OW working) and Buffalo are quite consistent in their firmware design, so that would be a plus.
Any advice from here would be helpful.
From the OpenWrt forum https://forum.openwrt.org/viewtopic.php?pid=371989#p371989
In terms of lexra (Realtek's reduced mips ISA) support, there is none - nor anyone actively pushing for it (as in providing patches/ pull requests against current master); chances for this to change are non-zero, but extremely low (once you'd have hypothetical lexra arch/ SOC support, there would still be the problem of the wlan drivers and current hostapd/ nl80211, to drive them reliably in AP mode).
[Disclaimer: I can't speak for the LEDE/ OpenWrt developers]
Personally I don't think lexra will 'ever' be supported in LEDE/ OpenWrt (too different from normal mips, no upstream/ toolchain support at all, very low-end devices, the wlan situation (drivers, AP mode reliability, nl80211 support) is difficult). But effectively all it would need, is someone pushing for it - to provide a (long-term-) manageable pull request with lexra support against OpenWrt/ master, kernel 4.14, musl, hostapd/ nl80211 for the wlan drivers and not too many arch specific changes (so it can be reasonably updated with the rest of OpenWrt and not stay behind).
Mind the difference between Mb and MB.
MX25L3206E is 32Mb = 4MB -> borderline, see https://openwrt.org/supported_devices/432_warning
Unsupported SoC and only 4MB sounds like riding a dead horse.
Indeed, misread '33,554,432 x 1 bit structure' in the PDF.
No need to spend time on this.
Thank you for the quick reply.