TLDR: On both my Mac and 2 windows machines the card shows up fine inside the device, but no CD-rom. Not sure what the deal is here.
Very strange, the isostick should completely ignore drives formatted as GPT, since it cannot read them. Not saying you are wrong, just perhaps something more is going on.
My first suggestion would be to check the cards for errors. I suggest using Windows for this; the procedure is as follows:
1. Right-click the flash drive in Explorer, go to Properties
2. On the Tools tab, under Error Checking, choose "Check now..."
3. Make sure "Automatically fix file system errors" is checked, and "Scan for and attempt recovery of bad sectors" is not checked.
4. Click Start
When that is complete, right-click the flash drive again and Eject it. Then unplug isostick, and plug it back in.
At the moment isostick will ignore a volume which has errors or was not cleanly unmounted/ejected, since it may cause the firmware to crash. Hopefully this fixes the problem! If not, read on...
Next I would suggest reformatting, using the SD Formatter tool for the 32GB card(s): https://www.sdcard.o...ds/formatter_3/
This will format the card FAT32/MBR and use optimal settings for the microSD card's internal management -- there's actually a tiny processor in each microSD card which, as far as I know, looks at the FAT32 filesystem to determine which blocks aren't in use and use them for better wear-leveling. This has the side-effect of increased performance with most cards.
As to the 64GB card(s), as you may already know Windows will refuse to format them FAT32, though I am unsure about MacOS X. In any case, this thread is full of apps and advice from people formatting 64GB cards to FAT32, and may be worth a look: http://reboot.pro/to...rosd-over-32gb/
If at this point things are still not working, you might try ISO Manager from Windows to load an ISO, and see if that fixes things.
If it still fails to work, well, we'll see what else can be done if that is the case 
1. When updating firmware both mine show up as "isostick emergency recovery (/dev/cu.usbmodem40121)" instead of what you said in the tutorial.
Good point, I will make a note to update the tutorial when I have some time.
2. Figuring out the direction of the card was fairly easy by looking in the hole, but knowing how far to push it in wasn't. I thought that I would be pushing it in too far and either damage the connector or lose the card inside the device.
Indeed this is confusing and fiddly. I intend to do a brief setup and usage video once the software is more refined (see below) and highlight these concerns, showing how to insert the card and so on.
In terms of actually improving the hardware, however, there is not much to be done. The card socket being used is a very high quality Molex part. Some enclosure changes are being made to improve the card insert/eject smoothness, but beyond that it just seems to be a fact that microSD cards are somewhat annoying to work with.
3. The crypticness/non-straightforward way this device works is fine for a Kickstarter thing, but I kinda expected something being sold on Amazon to be a little more polished...
Frustratingly, I completely agree. On Windows using ISO Manager the process is more refined, but still not nearly where I want it to be. I have been absolutely swamped with production and distribution issues, but those should be resolved some time early January, finally freeing up time for polishing things up.
ISO Manager will be polished up considerably, with a much better interface for enabling or disabling isosel, keeping it up to date, and providing diagnostics to aid in fixing bugs. And of course it will also be available for MacOS X and Linux. ISO Manager will display the current firmware as well.
Also I am playing with a patch for the firmware updater to eliminate the need to press the reset button, provided the isostick has a card, it's FAT32, writable, and the current firmware is working. The updater would write to a special file, much the same way iso_filename.txt works, then it would eject/unmount the isostick flash drive. That would signal to the isostick to go into update mode (after clearing the contents of the special file, so it doesn't get in an infinite loop of course 
).
Phew, long reply 
Thanks for your feedback and I look forward to getting this issue resolved for you and improving the firmware and software soon! 
