[Help] Upgrading path steps and Initboot USB location on F5-422

[Facy5]

Hello, I'm a bit new in the NAS world so excuse me if my questions are silly.

I bought a used F5-422 (BIOS version : MAPL0303V17). The previous owner never updated after TOS 4.2.44, and my goal is getting the lastest TOS 6 version. So I updated it, following the guide until TOS 5.1.24. Then, knowing the issue about the limitation of the 2Gb system partition, I donwloaded the Initboot file and flash it with Rufus on USB key.

But :

1) Where should the USB key go ? In the rear port, or do you have to disassemble the NAS to replace the internal USB key - and "sacrifice" the one I flashed inside the NAS (the guide doesn't tell it) ?

2) Can I flash the Initboot for TOS 6, replug my TOS 5 installed hard disk the continue updating to TOS 6, or do I need to fash the USB two time (first with TOS 5 Initboot + update to TOS 5.1.40, then flash with TOS 6 Initboot + update to TOS 6) ?

[MikeZhang]

Please check our guide below, you need to back up data, format drives then install TOS 5.0.176, and update to 5.1.145
viewtopic.php?t=4912

Then follow this guide to update to TOS 6
viewtopic.php?t=6809