You will probably want to contact support because they have changed the upgrade procedure a couple of times over the years. I am sharing below what has worked for me
If it ships with anything below 08080, upgrade to 08080e first as instructed.
Depending upon what it is running if before 08080, I would try a manifest upgrade to get to 08080e if that is supported. It probably is supported in any 08.0.70 but if your units come with an old 08.0.60 or 08.0.61 build I remember upgrading without a manifest.
You can do a "copy tftp ?" to see if system-manifest is offered.
You will undoubtedly need a TFTP server for any of these methods to work with any of the commands below as well as to configure an IP on the switches. A TFTP server is different than an FTP server. None of us endorse any certain one TFTP server product. Currently I tend to use TFTPD by Ph. Jounin, but there are other great ones such as by Solar Winds.
You may want to use the ? each step of the way because there are minor differences depending on the code you are running.
Manifest Upgrade Commands look something like this (it also upgrades the bootrom):
copy tftp system-manifest 10.1.2.3 FI08080e_Manifest.txt primary switch-image
copy tftp system-manifest 10.1.2.3 FI08080e_Manifest.txt secondary router-image
Obviously, you will want to look at the flash before and after "show flash"
If you need to do a legacy upgrade (i.e. because manifest commands not available):
copy tftp flash 10.1.2.3 mnz10114.bin bootrom
copy tftp flash 10.1.2.3 SPR08080e.bin secondary
copy tftp flash 10.1.2.3 SPS08080e.bin primary
I would recommend these checks, too regardless before reloading (rebooting):
verify md5 secondary
verify md5 primary
ONCE AT 08080e a UFI upgrade is the way to go. It also takes care of the bootrom:
copy tftp flash 10.1.2.3 SPS08090eufi.bin primary
copy tftp flash 10.1.2.3 SPR08090eufi.bin secondary
Once you are at 08090 builds, there is a default username and password, which is super and sp-admin. It's super annoying. Why not prompt for a password but not require one be set and force a default? Common sense would be to simply not allow any remote administration until the device is secured. At any rate, when you are prompted to change it, you are changing only the password. The logon name is still super.
If any of this is not mentioned, a common post is, "I upgraded to 08090 and cannot get in... how do I reset the password on 7xxx?" We have ALL done these typing test and test to get through the password prompts not paying attention. The result is not username test password test but rather still username super with password test.
Obviously, you can create other accounts, use RADIUS authentication, etc.
If it is your first time, you probably should contact support. You will certainly want to check that the boot-room is the proper version for the image and that the checksum is good prior to reloading. At any rate, getting support for an upgrade is less work than support for device recovery. I really doubt you will have any issues though. We have a couple hundred of these all of which have been upgraded at least half a dozen times without issue. The key is having them on reliable power prior to upgrading. If you loose power during a flash write, you are most likely going to have either the primary or secondary slot incomplete/un-bootable. If it is writing the bootrom itself, it would possibly brick the unit. This is of course true for any manufacturer's products when doing firmware upgrades.