Inside a Fortigate 100D Fortinet Firewall

We recently had a Fortigate 100D in the field fail to boot after logs were being written to the internal 16GB half mini MLC SSD for almost 3 years.

There is a warning when you choose to log to disk on the unit about reducing the life of the disk, however we decided to ignore :o(

We took the unit back to our office and through the CLI via console cable we could see that there were SCSI errors on POST - the unit couldn't see the internal half mini Solid State Drive which is where the firmware and log files are stored. A second SSD for logs would be a better design.

The unit was out of warranty, so I decided to open it up and see if the failed disk could be replaced. It turns out it can be, however a few things to consider:-

1. The boot rom on the Fortigate 100D formats the disk at 128Mb and the latest firmware uses over 240MB once expanded. To workaround this, I loaded FW 4.0 MR3patch7 and then upgraded to the latest at the time (MR3patch18) which expands the partition from 128MB to accommodate the larger storage requirements.
2. I had CRC issues when copying the firmware from a Windows 10 PC running tftpd32, and used Windows 7 with tftpd32 instead which worked without issue.
3. A 32GB Transcend Half Mini SATAII MLC Solid State drive was installed in place of the 16GB SSD shipped with the unit. At first when running 4.0 MR3 patch 7, it was only seeing 16GB - at first I though this was due to licensing limitations, however after upgrading to 4.0 MR3 patch 18 it detects the full 32GB (about 28GB usable).

 Some photos of inside the Fortigate 100D are below for anyone interested. The most obvious things you will see is the half mini SSD as well as the RAM.