Sniffle is a sniffer for Bluetooth 5 and 4.x (LE) using TI CC1352/CC26x2 hardware. Sniffle has a number of useful features, including: Support for BT5/4.2 extended length advertisement and data packets, Channel Selection Algorithms #1 and #2, all BT5 PHY modes, sniffing only advertisements and ignoring connections, channel map, connection parameter, and PHY change operations, and capturing advertisements from a target MAC on all three primary advertising channels using a single sniffer. This makes connection detection nearly 3x more reliable than most other sniffers that only sniff one advertising channel. Can write traffic to PCAP files for external analysis.
Requires a supported Bluetooth interface, such as the TI CC26x2R, CC2652RB, CC1352R, CC1352P, or the EC Catsniffer V3 CC1352. The documentation has a complete list of Bluetooth sniffers and links to get them.