Custom Linux on QNAP TS-673

Long long time ago… I installed a custom linux on my Lenovo EMC px6-300d. This machine served its purpose for almost 5 years. But now it’s somewhat aged and I feel like it is time to move on.

My new System, a QNAP TS-673 is equipped with a AMD64 based CPU, 32GB of RAM, 6 HDD Bays and 4x GBE. But as usual, I’m not happy with the shipped software and want to have full control on the system without all that cloud-stuff and online-madness.

The usual approach to gather some information about the system and start installing a new OS is to find and attach a serial console. The TS-673 has a almost undocumented serial port exposed using a 3.5mm 3-pin headphone jack in the back of the device. After some measurement and probing I found the following pin mapping: the shield (the bottom connector) is connected to ground, the ring (the middle connector) is RX (as seen from the NAS) and the tip (the top connector) is TX (also, as seen from the NAS). The levels are typical RS232 levels and the connection settings are 115200-8-N-1. After bungling up a connector cable and attach it to a RS232 serial converter I can see the device booting and the shipped Linux system is starting up.

After starting the device up and pressing F2 or DEL for a few seconds, I got the BIOS menu showing up. (While you browse through the menus, you can disable the annoying boot beep.) To start installing a custom Linux, I plugged a Arch Linux USB stick in one of the back USB-Ports and restarted into the BIOS menu again. Now, the USB stick can be selected for booting in the “Save & Exit” section of the BIOS menu. Make sure to select the entry Prefixed with UEAFI because otherwise the system will boot in legacy mode.

To keep the serial console alive for installation, the boot record must be edited by pressing e. The following string must be prepended:

console=ttyS0,115200n8

Now the ArchLinux installer is booting.

While installing, I moved the boot partition to the NVME device. This allowed me to remove the small internal USB attached flash completely.