RBS50 won't sync/ can't ping

Hi -

A few days ago I noticed my RBS50 was no longer sync'd with the RBR50 (wired backhaul) - just a constant pulsing white light.   I've tried most (if not all) of the tricks I've read here with no success:

• power cycle, resync using the buttons
• power cycle, resync using orbi app
• delete satellite from RBR50 web front end, re-add from orbi app
• Power cycle, sit orbis right next to each other (wireless), sync

It does not show up as a connected device to the router when it's plugged in to a wired ethernet port.

I've tried holding the reset button (with a paperclip) for 15 - 30 seconds on the satellite - the power light never turns amber.  I either get constant green, or solid red, or flashing red.  It seems flashing red means it might be corrupted firmware.  I've tried doing a manual connection through my computer (hardwire to RBS50, manually set computer ethernet IP to 192.168.1.10, ping either 192.168.1.1 or 192.168.1.250), but I can't  ping the RBS50.  This includes multiple variations (power cycle Orbi then try to connect; power cycle/reset button then try to connect, power cycle, wait 10 minutes, then try to connect).   I've tried to TFTP a new firmware version to 192.168.1.1 and 192.168.1.250, which of course has completely failed, likely because I can't ping the Orbi.  My computer thinks *something* is plugged into the ethernet cable, but I can't figure out how to get a response.

Any ideas, or is this satellite just dead?

Thanks