All available SFP GPON sticks on the market (Lantiq PEF/PEB 98035) including Zisa OP151S run on two OpenWRT versions
OpenWrt Attitude Adjustment 12.09
Linux version 3.10.12
http://archive.openwrt.org/attitude_adjustment/12.09/lantiq/falcon/
Openwrt Barrier Breaker 14.07
Linux version 3.10.49
http://archive.openwrt.org/barrier_breaker/14.07/lantiq/
Where is the falcon?
FALC-ON is back in 17.01 but it will be hard to find any prioprietary files for it.
http://archive.openwrt.org/releases/17.01.5/targets/lantiq/falcon/
Same for 18.06
http://archive.openwrt.org/releases/18.06.3/targets/lantiq/falcon/