So, I wanted to extract the running file system from the device. After som fiddling around I realised that the only file-transfer or pipe-tool (like netcat/socat) that existed was
wget, and it only supported plain HTTP, not HTTPS.
So I found this static ARMv6 build of well known busybox, that included full sets of tools. So I used it to spawn a temporary FTP-service that I could use to download the filesystem.
# flash partition cd /npc # download from http host on local server wget http://some.local.host/busybox # make runnable chmod +x busybox # create symlink for ftpd ln -sf busybox ftpd # run service ./busybox tcpsvd -vE 0.0.0.0 21 /npc/ftpd /
Complete rootfs with mtdblock-partitions (except mtd4 that is /rom)