Wireshark with the omci.lua and BinDecHex.lua plug-ins installed.
For the DFP-34X-2C2 OMCI logs capturing, configure the following option
# flash set OMCI_LOGFILE 1
# reboot
The logs will be available at /tmp/omcilog.
cat omcilog | sed -e 's/^/000000 /' > omci.hex
File -> Import from Hex Dump
Encapsulation Type -> Ethernet
set Ethernet -> Ethertype (hex): 88b5
Import
To have the omcilog converted to the pcap format, the following script should be used with the original omcilog file
text2pcap omci.pcp omci.pcap
After capturing don't forget to disable OMCI_LOGFILE 0