I've bought myself RB951Ui-2HnD OS LVL4 couple months ago (home usage mostly).
Recently I was struggling with some LTE Usb modems, no luck so far.... Anyway, I've noticed that since 6.40.1 there were some tweaks/updates including LTE fixes...
So I run an Winbox package update 6.40.1 -> 6.40.4... However after the reboot something is surely wrong. The router keeps rebooting itself each 3-5 seconds (just a quick flash on ACT+ETH4 leds and signal beep).
Routers behavior is pretty much the same as shown on YT:
https://www.youtube.com/watch?v=cjcXbBf91OA
I've tried recovering the "half-bricked" router using Netinstall tool.
I've also downloaded: all_packages-mipsbe-6.40.1 + routeros-mipsbe-6.40.1.npk. Using the netinstall how-to I've managed to successfully boot the router for netinstall communication - the device is properly shown in Netinstall device list. However - I have no clue how long should an upload take, it seems quite fast to me - the progress bar dissapears nearly instantly, router is shown with status: "Ready". After upload attempts the router is not rebooting automatically (perhapse it should, perhapse not...).
Anyway, leaving router for couple minutes does nothing. After manual turn off/turn on the router behaviour is the same as before (reboots repeatedly)...
Could use some help with 'resurrection procedures'...
PS. Problem solved. It seems there were some issues with netinstall <-> mikrotik communication. I ran netinstall on another laptop with fresh Windows OS. Netinstall successfully transfered all required packages to MT and it went back online after a reboot.