4G key and HDD at the same time

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Senior Member
I use an officially supported 4g key (E3276) as my primary and only WAN interface with my RT-AC68U running Merlin v380.70.
It looks I can't connect my E3276 (non-Hilink) and my external HDD at the same time to the usb ports of my router. If I do that, most ot the times (but not always) my E3276 doesn't appear in "Network Map" and the log looks like this: https://pastebin.com/2KeFpD9X
It doesn't really tell me anything special, but I've noticed these lines quite soon at bootup (no idea if it's normal):
Aug  1 02:00:17 WAN_Connection: WAN was exceptionally disconnected.
Aug  1 02:00:17 WAN_Connection: Ethernet link down.

The usb HDD always works, while the E3276 almost never works (I would say once over 10 reboots). Also, sometimes I manage to get it working by manually unplugging and replugging.
Of course the E3276 works perfectly if connected alone (that is to say without the usb HDD).

I've tried to swap usb ports between the two devices, enable/disable "reduce usb interference" option (for what it's worth), to no avail.

I can say this setup works perfectly with another 3g key of mine, but that's only 3g and that's why I'm switching to E3276.

Any hint? Usb power starvation when the dongle is booting, maybe?
Thank you so much for your insight.
Last edited:


Senior Member
Looking at the log I was wondering if the E3276 showing up as sdcard/cd-rom/modem at the same time is somehow misleading for the router.
Indeed, it is.
Problem solved by disabling on the E3276 all ports, but modem and PCUI. See here for details: https://superuser.com/a/1374158

No more detection issues!

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