Attempt to fix issue and remove unnecessary CFLAGS

Which issue? Your patch is ridiculously wrong in every way.

-CFLAGS = -O2 -Wall -Wextra -std=c99 -pedantic -Wno-unused
+CFLAGS = -std=c99

-O2 is unnecessary? Warnings is unnecessary?

-   if (!ret) ERR_EXIT("timeout reached\n");
+   while (!ret);

Will create an infinite loop if the device is not responding. And you won't see a warning about this. This usually happens when you unplug the device, but it can happen due to a bad cable connection.

You don't fix anything when you hide warnings.

ilyakurdyukov / spreadtrum_flash

Attempt to fix issue and remove unnecessary CFLAGS #5