Hi!
I was able to setup a 4g/LTE dongle (Vodafone k5005 AKA Huawei e398) on my netgear wndr3700 with attitude adjustment.
What I did was:
opkg update
opkg install usbutils usb-modeswitch-data
# Current usb-modeswitch-data package in AA doesn't support this dongle, so
# create the file /etc/usb_modeswitch.d/12d1:14c3 and paste there:
# Vodafone (Huawei) K5005
TargetVendor= 0x12d1
TargetProduct= 0x14c8
MessageContent="55534243123456780000000000000011062000000100000000000000000000"# After inserting the dongle it will enter "modem mode" and the device id shall be 0x14c8.
# Install more required packages
opkg install kmod-usb-serial-option
opkg install kmod-usb-net-cdc-ether
# Replace the content of /etc/modules.d/60-usb-serial
echo usbserial vendor=0x12d1 product=0x14c8 > /etc/modules.d/60-usb-serial
# Add support for 3g in luci
opkg install luci-proto-3g
# Now, go to luci and setup a new 3g connection in "Network -> Interfaces -> Add new interface"
# My dongle would only connect after executing gcom -d /dev/ttyUSB1 and inserting the pin code
# manually, BUT, it is possible to automate this 
In luci, go to "System -> Startup -> Local Startup"
# and insert
gcom -d /dev/ttyUSB1"# if the onboard sd card support is required
opkg install kmod-usb-storage block-mount
opkg install kmod-fs-ext4 kmod-fs-msdos kmod-fs-vfat
opkg install kmod-nls-utf8 kmod-nls-cp437 kmod-nls-iso8859-1
mv /etc/modules.d/60-usb-storage /etc/modules.d/59-usb-storage
There is no way to control things like connect only in 4g or prefer 4g to 3g in openwrt. Looks like the support for that exists in kernel 3.4+ through a module called *qmi*. But, if you select the preferred mode with the windows software client that comes with the dongle, it will remember it when connected to openwrt. So, if you select 4G mode only, when connected to openwrt it will connect to 4G only.
Good luck
Good luck
(Last edited by marc22 on 15 Nov 2012, 23:59)