I just got the E310 board and noticed that according to the Getting Started guide, you have to create a udev rule:
SUBSYSTEM=="tty", ATTRS{idVendor}=="1366", ATTRS{idProduct}=="1051",
MODE="664", GROUP="plugdev"
LABEL="jlink_rules_end"
If you create this rule in a Gentoo system, it conflicts with the ‘portage’ package manager. It is unable to install any package when this rule is active in udev. The fix that I’ve found is to set the other permission to 6. This allows both portage and the J-Link debugger to work. Is there any explanation for having the last bit set to only Read?