TL-MR3420v5 loses configuration after reboot

I have flashed it using tftpd. NOW thing is whenever i reboot or shutdown the router it loses all the configuration.First tftp then i did a sys upgrade "openwrt-mr3420v5-GO2019-03-10-samba-upgrade" please help.

root@Narutoworld:~# df -h
Filesystem                Size      Used Available Use% Mounted on
/dev/root                 6.0M      6.0M         0 100% /rom
tmpfs                    29.4M      1.0M     28.4M   3% /tmp
tmpfs                    29.4M    192.0K     29.2M   1% /tmp/root
overlayfs:/tmp/root      29.4M    192.0K     29.2M   1% /
tmpfs                   512.0K         0    512.0K   0% /dev

Does the same happen with an official image from


You're using a custom image that has too much crammed into it, going by the custom image name.

Note how your df output clearly shows your overlay missing (it's tmpfs in your case - ie RAM).

Check logread for pointers, pretty sure there's messages in there about there not being enough free blocks to set up a JFFS2 overlay and falling back to RAM.


Given the 6 MB rom size, I'm pretty sure that there is also a considerable amount of user (runtime-) installed packages on top, enough to overflow the overlay and make it unable to mount.


what should i do? i wanted the ROOter image so that my jiofi(usb dongle) can provide internet for longer period as on the stock firmware it keeps crashing?

i installed the "openwrt-18.06.4-ramips-mt76x8-tplink_tl-mr3420-v5-squashfs-tftp-recovery.bin"
and it did not lose any config even after power off but cannot access internet as it somehow does not get internet from usb dongle.

root@OpenWrt:~# df -h
Filesystem Size Used Available Use% Mounted on
/dev/root 2.5M 2.5M 0 100% /rom
tmpfs 29.5M 496.0K 29.0M 2% /tmp
tmpfs 29.5M 48.0K 29.4M 0% /tmp/root
tmpfs 512.0K 0 512.0K 0% /dev
/dev/mtdblock4 3.9M 292.0K 3.7M 7% /overlay
overlayfs:/overlay 3.9M 292.0K 3.7M 7% /

i am a complete noob in reading logs so i searched jffs2 in system log and found these

Thu Aug 16 07:51:23 2018 kern.notice kernel: [ 0.000000] Kernel command line: console=ttyS0,115200 rootfstype=squashfs,jffs2
Thu Aug 16 07:51:23 2018 kernel: [ 0.238366] jffs2: version 2.2 (NAND) (SUMMARY) (LZMA) (RTIME) (CMODE_PRIORITY) (c) 2001-2006 Red Hat, Inc.
Thu Aug 16 07:51:23 2018 user.notice kernel: [ 12.026759] mount_root: jffs2 not ready yet, using temporary tmpfs overlay
Thu Aug 16 07:51:49 2018 daemon.err mount_root: failed - mount -t jffs2 /dev/mtdblock4 /rom/overlay: Invalid argument
Thu Aug 16 07:51:49 2018 kern.err kernel: [ 49.266881] jffs2: Too few erase blocks (3)

Is the expected result, you don't have enough free space (>=3 erase blocks) for the overlay. The options are to go for a device with more flash - or to reduce the size of your firmware. For a 4/32 device, only the former is a viable option, while yours (h/w rev v5) seems to be a 8/64 one, that still is rather little for the amount of software you want to install.


thanks for quick reply. i cannot buy a new device as i recently purchased this and another stuff for my homeserver. how can i reduce the size of firmware?

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After my Career exam i will try to build it. Meanwhile i am reverting back to stock. Thanks to all for help and quick replies. See you soon.


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