Nothing else comes to mind unfortunately.
If the beginning of the card has been zero'd and a new structure put in place then there is nothing left over that could be interfering.
But so that I understand ..... you zero'd and recreated the structure & partition/s and formatted them outside the camera.
Yes, exactly that, in a normal USB card reader.
Could you then access those partitions on PCLOS, with the card in a card reader?
Yes, no problem, and in other devices, Android tab, WinXP (recognised and configured as webcam & USB Disk)
In the camera you then could not access the card .........
Not if I use the camera as a card reader (which it does fine with an 8GB card), but I could start the video recording and take stills with no problem.
but could you access it if it was subsequently taken out of the camera, and again put into a card reader?
I am trying to figure out if it is something written to the card while in the camera, or if it is the camera interface that is causing the problem.
The camera has the facility to format the card internally, which is necessary for the GUI config utility to recognise the card, it adds the label "VOLUME1" but other than that it's a normal FAT32 (LBA) format.
I initially tried to read the card, as delivered from the vendor, in the camera - no joy. Then tried it in the USB reader - OK. Then formatted in the camera - no joy reading in the camera, but would still read in a normal reader.
I *know* that the camera is capable of using up to 32GB SDHC, as there's a huge thread on it on RCGroups, but I imagine that most on there are running Windows.
I can always use this card in another device, and try one from another mfr in the camera if all else fails.
(I'm using the camera as a dash cam/PVR, so the camera deletes the oldest 5min video when the card is full, the max full journey recording is around 4hrs with 8GB.)