Hello.
I successfully updated online to the latest version of routerOS 7.16 on an RB760iGS hEX S.
I also successfully updated the routerboard firmware online.
After the reboot, the router no longer works, I cannot start the bootloader to load routerOS from the netinstall server.
I think a method of rewriting the bootloader in flash is necessary.
Documentation or tutorial?
Solutions?
Thank you!

All MT devices have "primary" routerboot and "backup" routerboot. When upgrading routerboot, one upgrades primary one. It's (almost) impossible to upgrade backup routerboot.

There's a procedure (button press) which selects backup routerboot ... and in that case, it should be possible to either boot ROS or at least enter netinstall mode (AFAIK the later doesn't help as netinstall does not upgrade routerboot on the go). So if you manage to start ROS (using backup loader), you should be able to re-install routerboot from within ROS.

https://help.mikrotik.com/docs/spaces/R ... RouterBOOT

If you don't succeed to proceed, then you'll have to open trouble ticket with support@mikrotik.com ... I don't think any "normal" member of this forum has enough experience to help you out if things are complicated. And this forum is user-to-user forum, not official means of support.