The Case of the Vanishing EMMC

[fxc]

The sd-card/sim slot wasn't attached properly. That has been fixed and I've reinstalled towboot. However I'm not out of the woods yet! I've tried postmarketOS, mobian and more recently manjaro (stable.) pmOS fails to boot as the /boot partition can't be found; Mobian gets a bit further and I get:

[1.403151] dw-apb-uart ff180000.serial: Failed to create device link (0x180) with 0-001c
[1.456703] dw-apb-uart ff180000.serial: Failed to create device link (0x180) with 0-001c
[1.475751] OF: graph: no port node found in /i2c@ff3d0000/typec-portc@22
[1.636224] mmc1: error -110 whilst initialising SD card
[1.804715] mmc1: error -110 whilst initialising SD card
[1.985690] mmc1: error -110 whilst initialising SD card
[2.199244] mmc1: error -110 whilst initialising SD card
[3.455033] pinephone-keyboard 5-0015: Failed to read device ID: -6

With manjaro I can get a shell and the emmc looks truly f0x0r3d.

Are you booting with RE or volume down? I'm asking because your above text is quite chaotic. For clarification:

* The RE buttons disables the eMMC and the SPI flash memory.
* Volume UP starts USB Mass Storage Mode (with Tow-Boot)
* Volume DOWN starts from microSD card (with Tow-Boot)

If you try to boot with RE it makes sense why it is not booting. RE disables the eMMC and SPI flash memory, however on the SPI there is Tow-Boot installed. Mobian and postmarketOS come with no bootloader and both need Tow-Boot. "MASKROM" means there is no valid OS found anywhere.

Only boot from microSD card with Volume DOWN.