Yes there are ten #0 Philips head screws. 6 long and 4 short. This computer was designed to be opened and tinkered with.
Do this:
1) open the "lid" 90 degrees, as you normally use a laptop.
2) turn the power off and insert a bootable SD card.
3) hang the monitor half over the edge of a table.
4) take the bottom cover screws out.
5) remove the bottom cover. It may be a little stuck. Note that the bottom cover is the entire strength of the bottom half. If you need to move or handle the PBP with the bottom cover off, only handle it by the monitor half, and don't try to operate the hinges.
6) turn the eMMC switch off. The location is described in the wiki. It's near the eMMC module (I think).
7) turn the power on.
8) at a certain point, early in the boot process, you can turn the eMMC back on. If you miss the opportunity, you can still attach and mount it later (I don't know how but there should be info in the wiki).
9) now you can either fix your fstab. If you like, you can put the bottom cover back on at this point. Be mindful of the shorter screws which go towards the front.
*also note that when the bottom cover is off, if you tilt the unit, small plastic parts (spacers) will fall out
When you're all done, it would be a good idea to install a different U-Boot or tow-boot that will actually allow you to boot from SD card in an emergency.
Do this:
1) open the "lid" 90 degrees, as you normally use a laptop.
2) turn the power off and insert a bootable SD card.
3) hang the monitor half over the edge of a table.
4) take the bottom cover screws out.
5) remove the bottom cover. It may be a little stuck. Note that the bottom cover is the entire strength of the bottom half. If you need to move or handle the PBP with the bottom cover off, only handle it by the monitor half, and don't try to operate the hinges.
6) turn the eMMC switch off. The location is described in the wiki. It's near the eMMC module (I think).
7) turn the power on.
8) at a certain point, early in the boot process, you can turn the eMMC back on. If you miss the opportunity, you can still attach and mount it later (I don't know how but there should be info in the wiki).
9) now you can either fix your fstab. If you like, you can put the bottom cover back on at this point. Be mindful of the shorter screws which go towards the front.
*also note that when the bottom cover is off, if you tilt the unit, small plastic parts (spacers) will fall out
When you're all done, it would be a good idea to install a different U-Boot or tow-boot that will actually allow you to boot from SD card in an emergency.