I'm always disabling interrupts while writing to some sectors on Flash, but does Flash memory requires disabled interrupts even when you just want to read from it? Why yes and why not? Thanks for the answer
No, you don't need to disable interrupts to read from Flash. Reading Flash is just like reading RAM. It's only writing which is different: inside the device a "high voltage" (just a couple of volts extra, really) is generated for the gate, and that gate voltage needs there to be longer than just a few nanoseconds to charge the floating gate. That is self-timed by the device.