Hardware reliability issues

[pfalcon]

Here I have a module which:

• Can get its flash programmed incorrectly (completely different data on read-back, no easily discernible patterns)
• After some boots may get stuck at early stages of bootloader, no reaction to reset or esptool.py. Pressing reset leads to just:

 ets Jan  8 2013,rst cause:2, boot mode:(3,6)


 ets Jan  8 2013,rst cause:2, boot mode:(3,6)


 ets Jan  8 2013,rst cause:2, boot mode:(3,6)


 ets Jan  8 2013,rst cause:2, boot mode:(3,6)

(each message is printed on each reset).

Only power-off (disconnect from USB) is what helps.

[pfalcon]

I just had an OTA update failure too (when OTA was sent completely, but after reboot, md5sum was found to be incorrect). This could be an issue in ota-server of course.