Arduino Yun no WiFi Access Point

Hello, I've bought and developed with an Arduino Yun board for two years, and have also previously used an SD card to expand its storage. However, I haven't used the board for a while, and also couldn't find its original SD card (I used the card for other boards, so either way it doesn't have the original Linino installation anymore...).

Recently I have come across some new projects that would find the Yun board useful, so I tried booting up the board. However, I could no longer see its WiFi Access Point (I might have set it to connect to the WiFi at home, but now I've moved to a new university with a different WiFi. So I've used WiFi reset - which should be able to reset the Yun board into AP mode - but still I cannot see the AP signal on my phone/laptop).

Using factory reset (i.e. pressing WiFi reset for >30s) doesn't help either. The board just keeps blinking its blue light (WiFi) and the USB light (white light) doesn't show up either.

The board's MCU part still works though, as I'm able to upload scratches from the IDE. I've tried to use the YunSerialTerminal scratch via USB connection, and the output is attached below. There seems to be some problem with the Linux part booting and preventing the WiFi AP from being set up (even though that this is after a factory reset, so the Linino distribution should be new...)

May I ask what are the best options I have for resetting the board? I wondered if it might be the problem of the SD card (since I'm formatted it and it doesn't have the original system data anymore). But either booting the board with the card in/out doesn't help. All tutorials on reflashing require either WiFi-connecting the board or Ethernet-connecting (which voids the warranty). Would there be some way to directly flash the SD card with Linino system on my PC (and perhaps boot the Yun board from the flashed SD card)?

Thank you for your help.

Error Log.txt (14.4 KB)

There is also a method to upgrade from SD card but I have not done it myself.

Will ask this post to be moved to the YUN specific section for you.