How to Properly Install and Use TOS 7 on the 425 Plus Series TNAS

[TMzethar]

Based on the information you provided, as mentioned on the first page of this thread, you will need to update your BIOS first in order to use TOS7 properly.
viewtopic.php?t=10182

[Din0]

If you are not using Slot 3, there is no impact, and you can upgrade directly to TOS 7.

Hi CursaYang,

Thanks for the confirmation. I have a general question regarding the BIOS update procedure itself for future reference.

The instructions always state that all drives must be removed before flashing the BIOS. Since removing NVMe drives from the motherboard is quite tedious compared to standard SATA drives, I would like to ask: why is it strictly necessary to remove them?

Is it merely a general safety precaution to protect user data in case of a flash failure, or does having the NVMe drives installed actually interfere with the BIOS flashing process or the subsequent boot/PCIe initialization?

Thanks for explaining!

[EriChan]

The requirement mainly comes down to two key points:

• Ensure a clean boot path: It prevents the NAS from accidentally booting into existing drives or old UEFI entries instead of the USB flasher. Since this BIOS update specifically fixes the Slot 3 NVMe boot priority, keeping NVMe drives installed easily introduces boot variables.

• Isolate storage devices: Flashing involves controller resets and PCIe/NVMe re-initialization. Removing the drives prevents abnormal disk access, partition table issues, or altered boot entries if an interruption occurs.

In short, it eliminates boot variables and protects your storage integrity.