Investigating affect of huge_app to the partition table bin when using esptool

[nitin710]

Feather details

Assembled Adafruit HUZZAH32 – ESP32 Feather Board

• 240 MHz dual core Tensilica LX6 microcontroller with 600 DMIPS
• Integrated 520 KB SRAM
• Integrated 802.11b/g/n HT40 Wi-Fi transceiver, baseband, stack and LWIP
• Integrated dual mode Bluetooth® (classic and BLE)
• 🟢 4 MByte flash include in the WROOM32 module 🟢

Current FW installer command

		command = command + " " + "--chip esp32 --port " + featherPort +
			" --baud 921600 --before default_reset --after hard_reset write_flash -z --flash_mode dio --flash_freq 80m --flash_size 4MB" +
			" 0x1000" + " " + ofToDataPath(ofFilePath::join("esp32","EmotiBit_stock_firmware.ino.bootloader.bin")) +
			" 0x8000" + " " + ofToDataPath(ofFilePath::join("esp32", "EmotiBit_stock_firmware.partitions.bin")) +
			" 0xe000" + " " + ofToDataPath(ofFilePath::join("esp32", "boot_app0.bin")) +
			" 0x10000" + " " + fwFilePath;

What each file means

• bootlaoder
  • should remain the same. See explanation in notes above
• partition table
  • specifies the partition of the flash. This will probably change if we use huge app
• boot_app0
  • The boot_app0.bin is the OTA data partition initial content. It is documented here. source

Notes

• Primary bootloader is outside the flash.
• Primary bootloader calls the secondary bootloader, which is programmed in the flash at address 0x1000
  • Second stage bootloader reads the partition table found by default at offset 0x8000 (configurable value). See partition tables documentation for more information.
  • The bootloader finds factory and OTA app partitions.
• The partition table is located at 0x8000
  • The partition table length is 0xC00 bytes, as we allow a maximum of 95 entries. An MD5 checksum, used for checking the integrity of the partition table at runtime, is appended after the table data. Thus, the partition table occupies an entire flash sector, which size is 0x1000 (4 KB). As a result, any partition following it must be at least located at (default offset) + 0x1000.
  • example partition table

 # ESP-IDF Partition Table
# Name,   Type, SubType, Offset,  Size, Flags
nvs,      data, nvs,     0x9000,  0x4000,
otadata,  data, ota,     0xd000,  0x2000,
phy_init, data, phy,     0xf000,  0x1000,
factory,  app,  factory, 0x10000,  1M,
ota_0,    app,  ota_0,   0x110000, 1M,
ota_1,    app,  ota_1,   0x210000, 1M,

partition table for ESP32

• https://github.com/espressif/arduino-esp32/tree/master/tools/partitions
• huge app partition table
  • https://github.com/espressif/arduino-esp32/blob/master/tools/partitions/huge_app.csv

References

• https://docs.espressif.com/projects/esp-idf/en/latest/esp32/api-guides/bootloader.html
• https://docs.espressif.com/projects/esp-idf/en/latest/esp32/api-guides/startup.html
• https://docs.espressif.com/projects/esp-idf/en/latest/esp32/api-reference/kconfig-reference.html#config-partition-table-offset
• https://docs.espressif.com/projects/esp-idf/en/latest/esp32/api-guides/partition-tables.html

[nitin710]

Comparing partitions

• default partition

# Name,   Type, SubType, Offset,  Size, Flags
nvs,      data, nvs,     0x9000,  0x5000,
otadata,  data, ota,     0xe000,  0x2000,
app0,     app,  ota_0,   0x10000, 0x140000,
app1,     app,  ota_1,   0x150000,0x140000,
spiffs,   data, spiffs,  0x290000,0x160000,
coredump, data, coredump,0x3F0000,0x10000,

• huge app partition

# Name,   Type, SubType, Offset,  Size, Flags
nvs,      data, nvs,     0x9000,  0x5000,
otadata,  data, ota,     0xe000,  0x2000,
app0,     app,  ota_0,   0x10000, 0x300000,// notice this combines both app0 and app1from default
spiffs,   data, spiffs,  0x310000,0xE0000,
coredump, data, coredump,0x3F0000,0x10000,

[nitin710]

Looks like all that needs to change is to have a new partitions bin that relates to the "huge app" setting. and everything else should remain same.
Will also need to implement logic that "if uploading BT binary" then "use huge app partition".

Confirm if this is required. We may not even need to change anything since the app always atarts at address 0x10000. What happens if the partition table says there is another app at location XX?

[nitin710]

If this is true [source]
"Only when you get around to writing your image into a specific device does it make sense to check if it fits, and the flasher tool does exactly that. Before that, it's your responsibility to do the arithmetic :)", then if the partition table does not allocate enough space for the app, then the esptool should fail?

[nitin710]

The EmotiBit FirmwareInstaller uses the bin files during the esptool step, because, i believe it is replicating platformIO build.

we may not actually need boot_app0.bin [source]

boot_app0.bin have to be some special partition in platformIO, because like you said, it is created with standard partition file. In esp-idf all you need are 3 partitions that are build during compilation:

• bootloader,
• partition_table,
• application