PCAP: U-Boot supports live Ethernet packet capture in PCAP(2.4) format. This is enabled by CONFIG_CMD_PCAP. The capture is stored on physical memory, and should be copied to a machine capable of parsing and displaying PCAP files (IE. wireshark) If networking works properly one can copy the capture file from physical memory using tftpput, or save it to local storage with (sf write, mmc write, fatwrite, etc) the pcap capturing requires maximum buffer size. when the buffer is full an error message will be displayed and then packets will silently drop. the actual capture file size is populate in the environment variable "pcapsize". Usage example: # Initialize pcap capture to physical address (0x100000) with maximum size of # 100000 bytes. # Start capture pcap start # Initialize network activity env set ipaddr 10.0.2.15; env set serverip 10.0.2.2; tftp uImage64 # Stop capture pcap stop # pcap init 0x100000 100000 PCAP capture initialized: addr: 0xffffffff80100000 max length: 100000 # pcap start # env set ipaddr 10.0.2.15; env set serverip 10.0.2.2; tftp uImage64 eth0@10000000: PHY present at 0 eth0@10000000: link up, 1000Mbps full-duplex (lpa: 0x7c00) Using eth0@10000000 device TFTP from server 10.0.2.2; our IP address is 10.0.2.15 Filename 'uImage64'. Load address: 0xffffffff88000000 Loading: ################################################################# ################################################################# ################################################################# ################################################################# !!! Buffer is full, consider increasing buffer size !!! ################################################################# ################################################################# ################################################################# ################################################################# ################################################################# # 18.2 MiB/s done Bytes transferred = 8359376 (7f8dd0 hex) PCAP status: Initialized addr: 0xffffffff80100000 max length: 100000 Status: Active. file size: 99991 Incoming packets: 66 Outgoing packets: 67 # pcap stop # tftpput 0xffffffff80100000 $pcapsize 10.0.2.2:capture.pcap