To enable presence of Ublox-M8 GNSS RX on LimeNET USB bus some modification is necessary:

USB Virtual Serial Interface: Connect the USB Differential Data Pins by soldering two 0R resistors to R96 and R97. The location of these resistors is on the top of the unit facilitating a lot the soldering process.

Useful links:

https://luigifreitas.me/2019-09-20/using-limenet-internal-gnss-constellation-monitor

https://wiki.myriadrf.org/LimeNET_Micro

https://wiki.myriadrf.org/LimeNET-Micro_v2.1_hardware_description

We use => Figure 2. LimeNET-Micro top side components and connectors

Green outlined arrow points to resistors location:

Now, before the modification we have:

pi@raspberrypi:~ $ lsusb
Bus 001 Device 006: ID 0403:601f Future Technology Devices International, Ltd
Bus 001 Device 005: ID 10c4:eac9 Cygnal Integrated Products, Inc. EFM8UB1 Bootloader
Bus 001 Device 004: ID 067b:2303 Prolific Technology, Inc. PL2303 Serial Port
Bus 001 Device 003: ID 0424:ec00 Standard Microsystems Corp. SMSC9512/9514 Fast Ethernet Adapter
Bus 001 Device 002: ID 0424:9514 Standard Microsystems Corp. SMC9514 Hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
pi@raspberrypi:~ $

After mod, we expect to see another device, something similar to:

Bus 001 Device 006: ID 1546:01a8 U-Blox AG

Soon, time to heat the soldering tip ;)