I ask for help from the community and the guys from technical support. When completing the MTCNA course, it was necessary to flash the latest firmware version v.6.46.5 of the RB962 router using Netinstall v.6.46.5. In the process of performing this procedure, some kind of failure occurred and the router was bricked.
I held the Reset button for 15-20 seconds until the SFP LED turns off, then released it so that RouterBOARD looked for Netinstall servers. But the device never appeared in Netinstall on Windows. My mistake was that I did not disable the firewall and the second network card. After that I fixed this error. I’ll clarify that both the IP address of the network card and the IP address of Net Booting Netinstall were originally set for the same subnet. The cable from the PC is connected to the Ether1 router. I repeated the reset procedure so that RouterBOARD looked for Netinstall servers, but no LEDs blinked anymore, only the PWR LED is constantly on.
I assumed something happened with the bootloader. And I used the instructions from the wiki (Manual: Reset: Loading the backup RouterBOOT loader). But holding the Reset button before connecting the power, and releasing it three seconds after turning it on, I still did not achieve any activity from the LEDs and the speaker.
After that, I took advantage of all the possible recommendations for recovery. I held the Reset button for a little more than 300 seconds before connecting the power (just in case, I used the device formatting function with the Protected Routerboot option active), although it was not active for me. In general, I tried all the possible recommendations of Wiki Mikrotik and some forums.
Whatever I do, only the PWR LED is on, no other LEDs blink or light up. There is no sound either.
I also have other Mikrotik devices (routers and switches). I repeatedly repeated the firmware procedure through Netinstall on other devices and everything went without any problems.
It turns out that there was no process of updating the firmware of the router. Please help me restore the device. The device is no longer under warranty. I’m ready to consider any methods, even related to JTAG, but with a description of actions, as I’m not very good at it yet. But be sure to figure it out!

I feel your pain I have the exact same unit and problem however I did a reset-configuration and loaded a backup (same device) and ended up with the blue led condition.

it appears the serial port does not work but jtag has some functionality if using a jumper wire on various tags you can power cycle the SOC (all led's simulate starting to boot) and even have a hardware link on ether 1 with a static IP on your pc but you wont be able to ping the unit.

I dont have a pc with a parallel port so cant do jtag programming. (There is a way to use a Usb uart serial device with resistors but thats lost info).
My unit is in this condition for a year now and it sucks as i cannot afford a replacement.

There is a post online somewhere that explains how to flash routerboot via jtag but my pc hdd crashed and I lost the info.

Mikrotik support flat out tell you to buy a new unit if its out of warranty and will not help at all.

I think you may have hit same problem as described here: viewtopic.php?t=149057
Total flash reset is dangerous as it probably wipes flash memory completely, including bootloader and manufacturing settings (why this function works this way is good question...!!!).

Firmware is stored in SPI memory and that is relatively easy to work with, it's just 8 pin SMD chip you can desolder easily, programmers are also cheap (CH341 + 3.3v mod will do the job) and if device is not booting at all, you don't even have to desolder it, just use SPI pads next to it to hook up programmer.
Recovery SPI memory contents will have to be read out from other hAP ac, this can be done from netbooting OpenWRT and dumping it there (no need for HW SPI access). Maybe you can find SPI dump somewhere on the internet, like on OpenWRT forums.

But you will probably hit same problem as original poster on the old thread: If you flash in contents from other device license will be invalid and all MACs and HW settings will be incorrect.
In that case you can probably still at least run OpenWRT on it, but not ROS, unless you convince support to generate new license for you.

Yes, really everything is just as you described. Problems are exactly the same as the user in the topic, the link to which you sent. I have not seen this topic before. Therefore, I himself came to this a few months after the publication of his post. In the router there is no SPI connector and a flash memory must be soldered. Then I purchased the CH341A programmer and just in case the new SPI Flash Winbond W25Q128FV. When I read Flash data, I saw that the first half was empty (FF). If you record Firmware from another of the same router, then mine also begins to work without a license. I have preserved my old MAC addresses and serial number. But in the firmware itself, only the serial is stored in the open form, the MAC addresses are somehow hidden (they cannot be found in the dump to replace). I then left everything as it is. After all, you constantly need to solder flash, which is not very pleasant ...
It would be nice to find out where and how the MAC address is stored, then everything could be restored. Only the question with the license will remain.