Mr6400 v4 it does not work

I have a problem on my mr6400v4, I installed openwrt via tftp, everything works fine. I have to use this router in LTE, I went back to the original software, again via TFTP it was completely installed upon reboot the router flashes. (doesn't start again). installed openwrt and everything starts fine. only works with openwrt.
what can I do? Thank you

what's your goal ?

getting it to work with openwrt, or going back to stock ?

go back to stock firmware.

did you dd the tp-link image before flashing it ?

https://openwrt.org/toh/tp-link/tl-mr6400_v4#debricking

LTE isn't enabled/configured in the openwrt image, you need to set it up from scratch, if that's why you decided to go back.

Yes, this is why I want to go back for the management of the LTE SIM. I did the reset, but the router flashes.

Or you could simply set it up in Openwrt.

No idea what the 2nd sentence means.

I tried, but when I put the original.bin file in /temp during the transfer I get the message "Not enough space"

the second sentence means: the router works 100% with openwrt, when I insert the stock firmware, it flashes on startup. Going back to openwrt everything works

then don't do the dd operation on the router ?
dd isn't an openwrt specific command.

restored original software via fttp, flashes when restarted. the installation seems ok.