It turns out that Phicomm T1 (not N1)’s firmware could be flashed onto N1, with “erase bootloader” enabled.

To connect N1 to computer I need to remove the lid of N1 and connect two pins (not sure how to describe this, TBH..). And flash T1’s firmware in, checking “erase bootloader” and “erase flash”.

Of course this won’t bring N1 back to life as T1’s SoC is not the same as N1 and T1’s firmware was not designed to be compatible with N1. In fact, even the flash process won’t complete.

However, what’s flashed in is completely enough to bring N1 to a “flashable” state, and after this it’s possible to flash firmwares for N1 after a power cycle.

I’m not quite clear about the rationale behind this, but I would guess that by using a workable SECURE_BOOT_SET it enables the burning tool to reflash a working bootloader onto the board. Even if the bootloader was not designed for N1, given its similarities with T1, it’s compatible enough to boot N1 into a flashable state. And this finally bring my first N1 back to life.