It turned out that sdkmanager setup to nano resulted in opted out 40gb. they neither could be allocated to a separate partition due to exceed of the number of existing partitions, nor could be added to existing partitions. could they?
lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
loop0 7:0 0 16M 1 loop
mtdblock0 31:0 0 4M 0 disk
mmcblk0 179:0 0 59,6G 0 disk
├─mmcblk0p1 179:1 0 14G 0 part /
├─mmcblk0p2 179:2 0 128K 0 part
├─mmcblk0p3 179:3 0 448K 0 part
├─mmcblk0p4 179:4 0 576K 0 part
├─mmcblk0p5 179:5 0 64K 0 part
├─mmcblk0p6 179:6 0 192K 0 part
├─mmcblk0p7 179:7 0 384K 0 part
├─mmcblk0p8 179:8 0 64K 0 part
├─mmcblk0p9 179:9 0 448K 0 part
├─mmcblk0p10 179:10 0 448K 0 part
├─mmcblk0p11 179:11 0 768K 0 part
├─mmcblk0p12 179:12 0 64K 0 part
├─mmcblk0p13 179:13 0 80K 0 part
└─mmcblk0p14 179:14 0 128K 0 part
sudo resize2fs /dev/mmcblk0 1
resize2fs 1.44.1 (24-Mar-2018)
resize2fs: Device or resource busy while trying to open /dev/mmcblk0
Couldn't find valid filesystem superblock.
sudo resize2fs /dev/mmcblk0p1
resize2fs 1.44.1 (24-Mar-2018)
The filesystem is already 3670016 (4k) blocks long. Nothing to do!