Hello, I'm new here, and I just want to thank everybody who have contributed to this thread, and to share my story with a pair of SB7700, just in case it is useful for anybody else:
I have a pair of SB7700 that have been powered on since one fellow of mine installed them almost 8 years ago. Recently, I had the need to move them from the rack where they were placed, so I had to turn them off. Of course, they didn't restart when I pluged them again. One of them showed in the console a message about not having any boot partition. The other one showed nothing at all.
After discovering this thread, I opened both of them. The one with no console output has a blown out capacitor, so that's the end for that one. In the other one, I was able to enter the bios, and after rebooting with the ONIE 2020.11-5.3.0005-115200 in a usb, I was able to start tinkering with it. I checked both of the SSDs, but they both were dead. I bought a Kinkston SSD, and I started the process that's described in this thread (for the SB7700, it seems that the right combination is CSM enabled + Non-UEFI ONIE, btw). I must mention that I was receiving some warnings related to the system not being capable of reading the serial number from TLV (or something like that), but the installation carried on. Searching about it I discovered that it was related to the EEPROM. I checked the content of the EEPROM with onie-syseeprom and it only had the verification checksum, all the other values were empty. But I carried on...
Even though in the first post it's said that the last version for the SB7700 is the 3.9.3124, I saw in the nvidia support page that they list the 3.9.3302 as the last supported version for the SB7700, so I tried with the installer located in the mega folder, the X86_64-3.9.3202-installer.bin. Unfortunately, after filling all the new partitions, near the end, the installation process failed with an error related to the mlxi2c command (MLXI2C_AUTO_DETECT_FAILED). However, I could boot MLNX-OS after the installation, but I had to wait for around 15 minutes from login in until I got to the prompt, and the output of 'show asic-version' showed that no managed switches were detected. I flashed many versions of mlnx-os via the update procedure, but none of them worked.
Then I started to suspect that the eeprom was more important than what I thought... I started to fill some fields with the information I could retrieve from the smbios, with dmidecode -t1. But the installation from onie to X86_64-3.9.3202-installer.bin always failed in the same place, with the same error (mlxi2c related). After more searches, I tried to fill some of the eeprom values that I had no idea how to fill... I located the onie-syseeprom dump from someone with a SN2100, and I noticed that there is a field Vendor Extension (0xfd) fields with hex numbers. I naively copied these fields, and after that the installation with the X86_64-3.9.3202-installer.bin worked... but it got all the values from a SN2100, so after restarting the system, mlnx-os still doesn't detect the asic. But I think that those values are the key to succesfully recover the switch.
Could anybody provide the onie-syseeprom dump from a working sb7700? Or maybe there is a way to get those values from the smbios and encode them in the right way, I don't know... Either way, any help would be greatly appreciated.
