Bootloader used to calculate the number of cache pages assuming that
load address was aligned, while in reality load address for DROM and
IROM was offset by 0x20 bytes from the start of 64kB page. This
caused the bootloader to map one less page if the size of the image
was 0x4..0x1c less than a multiple of 64kB.
Reported in https://esp32.com/viewtopic.php?f=13&t=6952.
Makes app image booting more reliable (256-bit rather than 8-bit verification.)
Some measurements, time to boot a 655KB app.bin file and run to app_main() execution.
(All for rev 1 silicon, ie no 340ms spurious WDT delay.)
80MHz QIO mode:
before = 300ms
after = 140ms
40MHz DIO mode:
before = 712ms
after = 577ms
40MHz DIO mode, secure boot enabled
before = 1380ms
after = 934ms
(Secure boot involves two ECC signature verifications (partition table, app) that take approx 300ms each with 80MHz CPU.)
* App access functions are all flash encryption-aware
* Documentation for flash encryption
* Partition read/write is flash aware
* New encrypted write function
