From this study, I learned the difference between the versions of initramfs and squashfs.
Because first 2 megabytes is occupied preloader and Uboot, I flashed a squashfs corresponding shift:
dd if = openwrt-18.06.1-mediatek-mt7623-7623n-bananapi-bpi-r2-squashfs-sysupgrade.bin of = / dev / mmcblk0 bs = 1M seek = 2
I received the following error when loading:
[ 1.510376] VFS: Cannot open root device "(null)" or unknown-block(0,0): error -6
[ 1.517797] Please append a correct "root=" boot option; here are the available partitions:
[ 1.526118] b300 7634944 mmcblk0
[ 1.526122] driver: mmcblk
[ 1.532898] b301 5120 mmcblk0p1 ffffffff-01
[ 1.532900]
[ 1.539649] b302 7567360 mmcblk0p2 ffffffff-02
[ 1.539652]
[ 1.546388] b318 512 mmcblk0rpmb
[ 1.546391] (driver?)
[ 1.553070] b310 4096 mmcblk0boot1
[ 1.553073] (driver?)
[ 1.559824] b308 4096 mmcblk0boot0
[ 1.559827] (driver?)
[ 1.566562] Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(0,0)
if I'm not mistaken, the root-filesystem should be on the squashfs section. but neither in initramfs nor in squashfs contains the signature "hsqs" denoting the beginning of the squashfs section. So in both images does not exist the root-filesystem ? Is that enough to open the issue?
I would very much like to get a working image from the openwrt site to facilitate future updates and ensure the compatibility of the opkg repository