Hi there, I got a pair of fairly generic SFP modules from AliExpress that came with an external media converter (RJ-45 to SFP). The SFP modules in question are labelled as SFP-WDM-SM-0205A and SFP-WDM-SM-0205B from the manufacturer ZOERAX. It is described as 1.25G 5KM T1550/R1310NM SC under the model name. You can find these here on AliExpress.
I have already confirmed that the modules work with the media converters and my fiber. When plugging it into the BPI-R4 sfp-lan, I get
[ 12.669557] sfp sfp2: Host maximum power 3.0W
[ 13.991206] sfp sfp2: please wait, module slow to respond
[ 16.016727] mtk_soc_eth 15100000.ethernet sfp-lan: configuring for inband/10gbase-r link mode
[ 16.060209] mtk_soc_eth 15100000.ethernet sfp-lan: entered allmulticast mode
[ 16.067366] mtk_soc_eth 15100000.ethernet sfp-lan: entered promiscuous mode
[ 69.612263] sfp sfp2: failed to read EEPROM: -ENXIO
# I removed the module here:
[ 597.492341] sfp sfp2: module removed
I tried i2cdump -y <N> 0x50 where were all buses from 0 through 5 but only got XX-es.
I used a multimeter to measure if MOD_DEF 0 is pulled to ground and was able to confirm that it is, so it’s not a power issue it seems.
Does anyone have an idea what could cause this? I found another thread with the same ENXIO i2c error but sadly it didn’t have any solutions: BPI-R4 failed to read EEPROM: -ENXIO from sfp
Edit: I don’t have anything in the M.2 M-key slot. The board only has the BPI-R4-NIC-BE14 module installed.