OpenWrt 18.06.2 - TP WR840N(EU) V5 - jffs2: Too few erase blocks (4 MB flash)

Hi All,

I just get a TP WR840N(EU) V5 and trying to flash OpenWRT.
unfortunately after downloading and flash from
image :,
I have issue that the settings are not persistent due to :

[ 7.956757] mount_root: jffs2 not ready yet, using temporary tmpfs overlay
26.030592] jffs2: Too few erase blocks (3)

Is the above firmware what I have used really for the WR840n v5 router ?
could you please recommend a different one what I can use, or maybe older version ?
Could you please advice how I can solve the issue ?

Thank you,
Best regards,

maybe some more info : my router has 4M flash / 64M RAM,

TP-Link TL-WR840N v5

MediaTek MT7628AN ver:1 eco:2

Firmware Version
OpenWrt 18.06.2 r7676-cddd7b4c77 /LuCI openwrt-18.06 branch (git-19.020.41695-6f6641d)

Kernel Version

My advice would be not to flash an older version but to use the Image Builder to strip any packages you don't need and build a new image. There's another trick to obtain a bit more free space (related to compression) but it's slipping my mind atm - and I believe you'd need to fully compile your own image for that.

Thank you for quick answer,
can I easily remove some package with Image Builder from the existing image please ? or do I need to build a completely new image ?

You are hitting the flash size limit. 4 MB devices are not that usable any more with the current OpenWrt.

Like Borromini suggests, build a personal image and try to strip unnecessary packages. You could strip some ppp packages etc. with imagebuilder, but the default release image does not contain that much unnecessary packages that you would have much choice...

Or use 17.01.6 or similar older build. Not perfect, but may work for you.

In general, just scrap the 4 MB device and use 30-50 EUR/USD to buy some current low-performance device with least 16 MB flash. 4 MB has not been that usable for years, and now with 18.06.x the limits are finally reached.

1 Like

Yeah you can.

Only if you would like to do anything more than removing packages from the image.

Thank you for all answers,

I can completely remove ex. IPv6, just need to be familiar first with the image builder,
do you have please some simple how-to how to remove some packages from the existing firmware ?

How about reading the wiki...

...or searching the forum:


Hi All,

Thank you very much for all help,
successfully created an image without IPv6 and Luci and all is working fine now.
adblock is great also,

do you have maybe some more proposal for "security" packages what is good to use in OpenWRT ?

OpenWrt in a default configuration is secure enough for most users, unless you manually change some options in firewall configuration or mess with iptables, which is considered advanced use.

Yes "for most users", but I mean bit more security - like filter out the crap - ads, analytics etc... - like the dnsmasq/adblock, arptables or other useful simple tools. Do you use maybe some more else what is useful ?

Well I don't use any extra stuff myself that would relate to security but you can head over to documentation at and look for yourself.

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