What version? A,B, or C?
I Have the three version, and in my case B version do not admit OpenWrt 19.07
I will check out if A and C can't save settings, and I will report it.
TP-Link WR902AC v1 also have this problem. Here's the output from OpenWrt 18.06, I've done a rollback because the router was unusable, and I have already installed some extra packages. I can install 19.07-rc0 again if it's needed.
BusyBox v1.28.4 () built-in shell (ash)
_______ ________ __
| |.-----.-----.-----.| | | |.----.| |_
| - || _ | -__| || | | || _|| _|
|_______|| __|_____|__|__||________||__| |____|
|__| W I R E L E S S F R E E D O M
-----------------------------------------------------
OpenWrt 18.06.5, r7897-9d401013fc
-----------------------------------------------------
root@OpenWrt:~# df -h
Filesystem Size Used Available Use% Mounted on
/dev/root 2.8M 2.8M 0 100% /rom
tmpfs 29.4M 576.0K 28.9M 2% /tmp
/dev/mtdblock4 3.1M 392.0K 2.7M 12% /overlay
overlayfs:/overlay 3.1M 392.0K 2.7M 12% /
tmpfs 512.0K 0 512.0K 0% /dev
root@OpenWrt:~# cat /proc/mtd
dev: size erasesize name
mtd0: 00020000 00010000 "u-boot"
mtd1: 00730000 00010000 "firmware"
mtd2: 00152620 00010000 "kernel"
mtd3: 005b0000 00010000 "rootfs"
mtd4: 00320000 00010000 "rootfs_data"
mtd5: 000a0000 00010000 "tplink"
mtd6: 00010000 00010000 "art"
tp-link tl-wr841n ver 11.1 is not saving changes across reboots..
using the tiny build..
BusyBox v1.30.1 () built-in shell (ash)
_______ ________ __
| |.-----.-----.-----.| | | |.----.| |_
| - || _ | -__| || | | || _|| _|
|_______|| __|_____|__|__||________||__| |____|
|__| W I R E L E S S F R E E D O M
-----------------------------------------------------
OpenWrt 19.07.0, r10860-a3ffeb413b
-----------------------------------------------------
root@OpenWrt:~# df -h
Filesystem Size Used Available Use% Mounted on
tmpfs 13.5M 68.0K 13.4M 0% /tmp
tmpfs 512.0K 0 512.0K 0% /dev
root@OpenWrt:~# mount
rootfs on / type rootfs (rw)
proc on /proc type proc (rw,nosuid,nodev,noexec,noatime)
sysfs on /sys type sysfs (rw,nosuid,nodev,noexec,noatime)
tmpfs on /tmp type tmpfs (rw,nosuid,nodev,noatime)
tmpfs on /dev type tmpfs (rw,nosuid,relatime,size=512k,mode=755)
devpts on /dev/pts type devpts (rw,nosuid,noexec,relatime,mode=600,ptmxmode=000)
debugfs on /sys/kernel/debug type debugfs (rw,noatime)
root@OpenWrt:~# cat /proc/mtd
dev: size erasesize name
mtd0: 00020000 00010000 "u-boot"
mtd1: 003d0000 00010000 "firmware"
mtd2: 0036904b 00010000 "kernel"
mtd3: 00050000 00010000 "rootfs"
mtd4: 00010000 00010000 "art"