Backing up file system for flashing

[ma261065]

Hi all,

I'm putting together instructions to a fab house to flash the boards that they are making for us.

I want to include our application files, but I don't want to "freeze" them in a firmware image, as I just want to use a stock image.

Is it "supported" to do the following steps to achieve this:

1. import esp32
esp32.Partition.find(type=esp32.Partition.TYPE_DATA)

This will list the data partitions. The filesystem is stored in the label=vfs

Make note of the address and size of the vfs partition (mine were address=5177344, size=11599872) and convert them to hex (address=0x4f0000, size=0xb10000 in my case)

2. Make a backup of the file system using: esptool -p COM4 -b 460800 --before default_reset --after no_reset --chip esp32s3 read_flash 0x4f0000 0xb10000 fsbackup.bin

3. Then when they flash the chip from scratch, they can just include that file. e.g.

esptool -p COM4 -b 460800 --before default_reset --after no_reset --chip esp32s3 write_flash --flash_mode dio --flash_size detect --flash_freq 80m 0x0 bootloader.bin 0x8000 partition-table.bin 0x10000 micropython.bin 0x4f0000 fsbackup.bin

Also, is there any need to back-up and restore any of the other data partitions? (i.e. nvs, otadata, phy_init)

[jimmo]

@ma261065 Yes this is definitely supported.

FWIW, I'm guessing you're using a 16MiB-OTA configuration, in which case these numbers come from the partiton table: https://github.com/micropython/micropython/blob/master/ports/esp32/partitions-16MiB-ota.csv

(you can also extract this out of partition-table.bin, which is generated from that csv file)

For a given flash size + configuration, these offsets and sizes must remain fix, otherwise new firmware updates will be unable to access the filesystem partition.

For the other partitions, only nvs if you're using NVS (and want to restore that data).

[ma261065]

Thanks Jim. Yes, I'm using the 16MiB-OTA configuration.

I don't know what the NVS partition is used for, so I don't know whether I need to back it up or not...

[jimmo]

@ma261065 http://docs.micropython.org/en/latest/library/esp32.html#non-volatile-storage

[ma261065]

Got it, thanks. I wasn't sure if it was used by MicroPython itself for anything, but it looks like it's just a data store for the application to store key/value pairs in, which I'm not using.

All clear now - appreciate the response.