Getting ghosted by support

[FranklyFlawless]

@Dlonk

I read on the forums that there’s something loose in the L5 that damages SIMs and SD cards as they enter and exit the device unless the device is completely powered off when you remove and insert the SD/SIM tray.

@eegerferenc

What I found out:

• The combo card socket is such, that the SD part’s contacts sweep over the SIM card while the tray is moved
• The SD card power supply contact is always energized, even when the tray is pulled out (tray detect switch is disengaged), contrary to both ISO 7816 (which requires all contacts to be de-energized and disconnected immediately upon the beginning of removal of the card) and common sense
• The relative arrangement of the SIM and SD contacts result in 3.3V with reverse-polarity to be applied to the SIM power supply pad and then clock, then reset pads in while the tray is pulled out (and in reverse sequence when it is pushed in), damaging the SIM card and also possibly over-stressing U43 (power switch of SD card)

A possible fix to this problem that can be made by Purism in future releases of the mainboard is to make sure that disengagement of the tray detect switch disables the SD card power immediately in hardware, for example, by adding an additional pull-down transistor at TF_PWR_3V3_EN driven by TF_NCD or 4G_SIM_CD depending on the card detect switch’s operation. Also, what can be done meanwhile is updating the documentation to make it explicit that the “don’t remove the SIM tray while the phone is on” statement is not a customary warning that can be routinely ignored, but a workaround of an otherwise serious hardware bug.

@Dlonk

I also have had support not reply sometimes and reply others, but once someone pinged JCS and got JCS on the case, they replied back again. I’m not sure exactly how that works.

Mentions within the Getting ghosted by support thread are generally escalated. Outside of that thread, mentions are unreliable.

@irvinewade

After an appropriate amount of time, and assuming still no response, you can also try pinging @‌JCS to see whether he can follow up on your behalf.