Lost connection to SFP module

Hi, I'm sorry for posting this. This problem may not be connected to OpenWRT itself, it may be hardware problem. But I can't find any solution, so... maybe you can help?

I have BPI-R3 router and have OpenWRT running on it. I bought DFP-34X-2C2 sfp-module recently. I connected it to router without problems, got internet connection (I use EPON connection type).

But then I changed LAN_SDS_MODE to 4 (default was 3) on sfp module.
https://github.com/Anime4000/RTL960x/blob/main/Docs/FLASH_GETSET_INFO.md#lan_sds_mode
After this sfp module "disappeared". I can't connect to it anymore.

Checked ethtool. Here is output (eth1 is device, where sfp-module connected):
249265222-faa0ded2-1535-4ed0-a23f-e2676c0d2897

From log:

Tue Jun 27 23:13:37 2023 kern.info kernel: [ 24.870354] mtk_soc_eth 15100000.ethernet eth1: Link is Up - 2.5Gbps/Full - flow control off

Tue Jun 27 23:13:37 2023 daemon.notice netifd: Network device ‘eth1’ link is up

Also no Rx on eth1:
29f4199faef976f3d2c7fe4df4c5c9280af8624f

Can I do something to make sfp-module visible? Or UART to sfp is an only option now?

Though I don't believe this is specifically OpenWrt related, have you tried flashing it back to 3?