Ok, BTW I've built another firmware with gpioctl included (also with samba, and pure-ftpd). The usb modules for external storage are included, also for FAT, EXT, NTFS(read only) filesystems, I need to know if at least the usb stick is detected in the kernel log when you plug and unplug it.
openwrt-HG655x-squashfs-cfe-5.bin
Once you get the GPIOs assignments for buttons and leds, I'll made a patch with all the stuff to integrate your router in a git repository. Official support for bcm63xx it seems got stucked with the dts migration, thus it might be eventualy supported.