Connect your Telraam device with wired ethernet instead of Wifi, using a USB2Ethernet Dongle like https://www.amazon.de/gp/product/B00MYT481C/
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Download Telraam dev image https://github.com/Telraam/Telraam-RPi/blob/master/telraam-dev-image
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Flash the image on the SD card
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Before putting the SD card into the Raspberry Pi, add the empty file "ssh" in the root of the SD card ("touch ssh")