Hey Tony,
I would have asked how exactly you all can see a causal relationship between this crashing event and a damage of the Operating System’s SD card filesystem, requiring re-flashing the entire SD card. I’d REALLY be interested in someone explaining that to me!
Ah, here we have the culprit. As Onefinity confirmed here, hitting the red mushroom-shaped button on the top of the black Onefinity Controller case does not trigger the buildbotics “Estopped” mode, but only cuts the DC power to the Onefinity Controller mainboard and does nothing else (and unlike in real buildbotics “Estopped” mode, hitting this button does not stop router and spindle!). Also it brutally cuts power to the internal Raspberry Pi which can cause filesystem errors 
. That is why I repeatedly warned about using this button AT ALL and recommended wiring this button to the “estop” pin 23 on 25-pin I/O port instead, which then would trigger real buildbotics “Estopped” mode (which also stops spindle and IoT-relay-attached router then!) and does not brutally cut power to the internal Raspberry Pi, so won’t cause filesystem corruption on the SD card.
Just like any computer, interrupting power on the internal Raspberry Pi 3B inside the Onefinity Controller during a write operation on the filesystem is likely to cause filesystem corruption with possible data loss. THIS is likely to entail the necessity to reflash the entire SD card.
So, Tony, if you intend to further use this non-smart brutal button on the top of the black Onefinity Controller case, that DOES NEITHER trigger buildbotics “Estopped” mode (if you don’t wire it to estop pin 23 on breakout board adapter instead) NOR stops router or spindle on emergency, I strongly suggest to always have a SD card writer on hand, as using this button is likely to corrupt the filesystem of the SD card everytime you use it.
Alternatively to hitting this malwired button, you can click on the red/yellow “Estop” icon on the top right corner of the screen. This one REALLY enters buildbotics “Estopped” mode:
More Information
Connecting Emergency Stop button to the Onefinity Controller breakout board
to trigger real “Estopped” mode
To use the buildbotics “Estopped” mode with your red mushroom-shaped Emergency Stop button, you wire it to ‘EStop’ (Pin 23) and ‘Ground’ (Pin 25) (=Logic low) on 25-pin I/O port (e.g. via the breakout board adapter)
Image: Emergency stop switch with case for external mount
If you connect a “Normally Open” Switch (NO), in the “I/O Configuration” Tab, “estop” on the SETTINGS page must then be set to “normally open”. If you connect a “Normally Closed” Switch (NC) you must set it to “normally closed”.
Excerpt from Buildbotics 25-pin I/O port (breakout board adapter):
| PIN | NAME |
| POSSIBLE VALUES | DESCRIPTION |
|---|---|---|---|---|
| 23 | EStop |
| Open, VIL | Emergency stop switch |
| 25 | Gnd |
| Ground | |
| 20 | +3.3 V | O | V3.3 | 3.3 volt source, 26.1 ohms source impedance (see note) |
Note - The following table defines the logic values that are used.
| LOGIC NAME | MINIMUM | MAXIMUM | DEFINITION |
|---|---|---|---|
| VOL | 0 | 0.76 VDC | Logic output low |
| VOH | 2.6 VDC | 3.3 VDC | Logic output high |
| VIL | 0 | 0.6 VDC | Logic input low |
| VIH | 2 VDC | 3.3 VDC | Login input high |
| V3.3 | 3.3 VDC | Voltage found on V3.3 Output when unloaded |