We fight with this topic some time ago,
to resume a little bit:
The GPON ONU is a different kind of transceiver than no have a traditional eeprom inside, instead uses a nor flash chip (8, 16, 32 mb depending on the manufacturer) and is emulated their access after the OS was loaded/booted, this kind of transceivers have a embedded linux inside with the specific onu/omci drivers and all other features than each manufacturer want to add it, like the MAC.
the GPON ONU have two versions:
1- without MAC, that means than the gpon no have a accessible network interface configured to we can configure it, comes already preconfigured and only can be provisioned via omci from OLT side.
2- with MAC (Sticks), that means than the gpon have an accessible network interface and a method to do that, like telnet, ssh, or web (linux services), there you have the possibility to configure/debug it.
in the case of Mikrotik ONU is a kind of transceiver from the first group, in their case have pre configured the basic details (SN and PLOAM Password) from factory, and that information is stored on both sites:
1- In the "EEPROM" used by the other devices where is connected this SFP for know what kind of transceiver is and for persist some changes like sn, ploam password and more
2- in the same firmware img: inside of the configuration files used by the PON, OMCI drivers. in the most of cases (with MAC transceiver) this have a default value than is updated on boot time getting the value from "EEPROM".
the problem is than the GPON ONU of mikrotik no updates the sn, ploam password, etc in the config files inside of filesystem at boot time, because was made as a pre-provisioned transceiver, in other words, you can not change this values from client side, only can be configured in the OLT side to be discovered. take in count than the filesystem is readonly when was mounted in boot.
the trick here is (the most complicated part), update the files where is stored the SN and the PLOAM Passwd (SLID), rebuild the filesystem, recalculate the CRC Checksum and rewrite the nor flash. to you can be able to complete the authentication process with the OLT. you should be update the values in both sides filesystem and EEPROM (remember is a virtualized EEPROM inside of nor Flash and only can be accessed before the SFP boot completely vía IC2 eeprom programmer or via comand_cli if the gpon have this feature available).
this is a very expensive procedure and only the peoples with a very good skill on this areas can make this change for their own.
all GPON ONU (and in general SFP) have a two wire console access to debug and configure using an EVM Board (Evaluation Module Board) than provide network access to the GPON (only for Sticks) and Serial Console access.
we speak a lot of times with mikrotik to perform a firmware update and give the MAC capabilities to their GPON ONU, but they are no interested on spend resources on make this changes, as many other manufacturers.
for this reason we develop our own GPON ONU Stick with this features and more.
more details here: https://www.facebook.com/CarlitoxxPro/p ... 1173849605
I hope than i've clarify a little bit more this topic for some people.