Realunix Pro Hg680p Install Guide

What to expect:

Default Credentials:

Login: root
Password: realunix

If no HDMI output: Use serial TTL (GND, TX, RX on 3.3V header). Connect via:

screen /dev/ttyUSB0 115200

The HG680P requires a specific key combination to boot from external media.

| Problem | Likely Cause | Solution | |---------|--------------|----------| | No boot, red LED only | Wrong DTB or bad SD write | Re-check DTB name; use serial to see U-Boot errors. | | Ethernet not working | MAC address collision or wrong PHY driver | ifconfig eth0 down; ifconfig eth0 hw ether 00:11:22:33:44:55; ifconfig eth0 up | | eMMC install fails | Write-protect jumper | Locate WP pad and disconnect from GND. | | Kernel panic after boot | Overheating or bad power supply | Use 5V/2A adapter; add heatsink to SoC. | | USB ports dead | Missing VBUS enable GPIO | In DTB, check usb@c9100000 and vbus-regulator. | | SD card not detected | Voltage mismatch (1.8V vs 3.3V) | Add sd-uhs-sdr12 to DTB to force 3.3V. |

Serial U-Boot rescue commands:

# Force boot from SD
setenv bootfromsd 1
saveenv
reset