Hey guys,
pretty much it: I have a RB951G that is recognised by netinstall, and in wireshark capture on PC I see BOOTP exchange working, ros file is being transferred to RB.
However, after this nothing happens. Netinstall says "sending reboot command" and then I see no blinking of LEDs no matter where I insert the cable (tried all ports),
and also wireshark capture shows no activity from RB. I'm not an expert but from the look of it I conclude that 951 is dead? Probably something with memory chips or something?
I think it does not boot on it's own.
Any ideas?
BTW I tried netinstall+packages 7.23 and 6.49.6

Maybe yes, maybe no...
What was the initial reason that led you to netInstall the device ?

the owner says it stopped working and gave it to me to check if it can be revived. No prior history, I've got it in this state.

Remember two main tip for netinstall....

• use a switch between your PC and RB - PC can up interface slowly... and netinstall then can not work properly
• monitor in Wireshark if a incomming request BOOTP starts... then you know you can release button, this give you confirmation that booting process ask about recovery.

of course are more stuff and netinstall is not perfect but with this it's easier to work. Other tips I write here: HowTo NetInstall

But your example probably have problem with NAND :(.
I remember that ppl can replace it, request about license to MikroTik and recover that unit.

If it was any regular embedded Linux machine, you would simply connect UART console and get some kernel bootlog with error messages that would tell you exactly why it's not booting.
But this is Mikrotik and they do everything to block this type of access, so it's just a black box: It either works or it doesn't and you are supposed to trash it and buy a new one.

If you don't want to give up that easily: I would first open it and check usual suspects like all electrolytic capacitors on board, any PCB damage etc.
Then connect the UART console pins and try netbooting OpenWRT. You will get proper kernel bootlog messages and if it boots, you can test everything, work with NAND/flash chip etc.
If hardware seems to be working, maybe try some older netinstall and ROS version. Another option might be to dump and write back the NAND contents, as that may mark some bad blocks.. or try to install OpenWRT to NAND (but make sure you dump original contents first in case you later want to go back).

But the main thing is to boot something usable for troubleshooting...

The only other suggestion I would make is to check the power supply. A bad or failing PS can have many different symptoms.