After having problems with SD cards failing after a few months in a Raspi that was supposed to be always-on, it was time to look for options.
The IPE distribution seemed like a perfect match – it effectively makes the Raspi only use a ramdisk, except possibly during boot. When needed the SD card file system can be made writeable, meaning that apt-get etc can be used as usual to install apps.
This worked great for ca 3 weeks, then this setup ALSO failed, with the same symptoms as before: at boot only the red power light would come on – nothing else. A fresh SD card with a fresh copy of IPE worked fine in the same Raspi hardware, thus not the Raspi itself that had fried (the cabinet where it lives is kind of warm, nothing too crazy though).
Now the weirdness starts for real. The failing SD card works perfectly fine when inserted in both an iMac and a Windows laptop. I spent hours and hours reformatting the card with various low-level tools, then writing the standard Raspian image to the card. Just for reference I did the same to a third SD card too, that card was identical to the failing one.
Still the same issue: that one card would still prevent the Raspi from booting.
The card in question is a Kingston 16 GB microSDHC card marked SDC4/16GB 081. It comes with an adapter that makes it usable also in large SD card connectors.
Finally, and I of course should have thought of this sooner, I tried swapping the two different microSD to SD adaptors. And of course… the solution was simple. It was not the SD card that had failed, it was the adapter. For some reason (heat? just poor quality?) the adapter had a small crack in its plastic housing, and as a result most likely some poor connection inside, between the microSD card itself and the surrounding adapter. When inserted into a proper computer, there was probably enough pressure on the adapter to squeeze it against the actual microSD card, while the SD card holder on the Raspi is kind of flimsy, and did not provide the needed pressure. When using a working adapter all three microSD cards work flawlessly in the Raspi.
Note to self: Use full sized SD cards in Rasperry Pis….