TL-MR6400 v5.2 4G Modem

I am new to OpenWrt an need some help with acitvating the 4G modem in my TP Link TL-MR6400 V5.2.
I managed to install OpenWrt by TFTP Method. When connecting WAN to a serperate Rooter/Modem Internet works fine over Ethernet and WLan.

But now I would like to use the internal 4G Modem.

Is there some software package that can just easysly be installed over the GUI?
I tried installing qmi-utils but failed.

failed how ?

Collected errors: * verify_pkg_installable: Only have 876kb available on filesystem /overlay, pkg glib2 needs 900 * opkg_install_cmd: Cannot install package qmi-utils.

The opkg install command failed with code 255

have you installed any additional packages ?

if not, that's all the space you've got ...

I installed manualy over Lucy openvpn-openssl and luci-app-openvpn so far.

In the end I am not commited to a special software package. I just need any solution to access cellular internet, while being able to use the rooter as a vpn client. The native firmeware does not support use as vpn client.

that's the memory, just as the title says, flash space info is found in the software menu.

Thanks for your fast reply. So because 900 KB are needed and only 897 KB are free, I have to remove some software to make space for the installation?

Is only qmi-utilis required?

Which software should I get rid of?

You can only remove what you installed yourself, removing packages that came with the image, doesn't free up any additional space.

If you need a smaller image (= more flash space available for packages) you'll have to create one yourself. might be of help.

OK thanks.

I managed to install qmi-utils. But after creating a new connection, selecting my modem and putting in my apn credentials, nothing happened. I did not get any IP address.

Has anyone gotten LTE running with the v5.2 model yet?
As a beginner I won't manage this on my own.