Cannot read flash partition

[DaneSlattery]

I cannot read flash partitions with espflash on an esp32-s3 devkit over UART.

[2024-10-25T10:47:14Z INFO ] 🚀 A new version of espflash is available: v3.2.0
[2024-10-25T10:47:14Z INFO ] Serial port: '/dev/ttyUSB0'
[2024-10-25T10:47:14Z INFO ] Connecting...
[2024-10-25T10:47:14Z INFO ] Using flash stub
Chip type:         esp32s3 (revision v0.2)
Crystal frequency: 40 MHz
Flash size:        8MB
Features:          WiFi, BLE
MAC address:       30:30:f9:55:19:54
Error: espflash::read_flash::corrupt_data

  × Corrupt data, expected 1000 bytes but receved fd1 bytes

I am able to do the same with esptool.py:

esptool.py read_flash 0x9000 0x6000 ./nvs_dump.bin
esptool.py v4.8.1
Found 33 serial ports
Serial port /dev/ttyUSB0
Connecting....
Detecting chip type... ESP32-S3
Chip is ESP32-S3 (QFN56) (revision v0.2)
Features: WiFi, BLE, Embedded PSRAM 8MB (AP_3v3)
Crystal is 40MHz
MAC: 30:30:f9:55:19:54
Uploading stub...
Running stub...
Stub running...
Configuring flash size...
24576 (100 %)
24576 (100 %)
Read 24576 bytes at 0x00009000 in 2.2 seconds (90.0 kbit/s)...
Hard resetting via RTS pin...

I don't know what is missing?

[MabezDev]

Can you try again with --no-stub?

[DaneSlattery]

Here's the result:

espflash read-flash --no-stub 0x9000 0x6000 ./nvs_dump_devkit   
[2024-10-25T10:45:55Z INFO ] 🚀 A new version of espflash is available: v3.2.0
Error: espflash::stub_required

  × This command requires using the RAM stub
  help: Don't use the `--no-stub` option with the command

[zakimoo]

same hier

espflash read-flash 0x0 0x0400000 test_3.bin

[2024-11-21T14:48:38Z INFO ] Serial port: '/dev/ttyUSB0'
[2024-11-21T14:48:38Z INFO ] Connecting...
[2024-11-21T14:48:38Z INFO ] Using flash stub
Chip type:         esp32c3 (revision v0.3)
Crystal frequency: 40 MHz
Flash size:        4MB
Features:          WiFi, BLE
MAC address:       a0:76:4e:5a:41:70
Error: espflash::read_flash::corrupt_data

  × Corrupt data, expected 1000 bytes but receved fcf bytes

but with esptool.py it works

esptool.py -b 460800 read_flash 0 0x0400000 flash_contents.bin
esptool.py v4.8.1
Found 1 serial ports
Serial port /dev/ttyUSB0
Connecting....
Detecting chip type... ESP32-C3
Chip is ESP32-C3 (QFN32) (revision v0.3)
Features: WiFi, BLE, Embedded Flash 4MB (XMC)
Crystal is 40MHz
MAC: a0:76:4e:5a:41:70
Uploading stub...
Running stub...
Stub running...
Changing baud rate to 460800
Changed.
Configuring flash size...
4194304 (100 %)
4194304 (100 %)
Read 4194304 bytes at 0x00000000 in 106.9 seconds (314.0 kbit/s)...
Hard resetting via RTS pin...

[liclac]

Same here, also trying to dump the default NVS partition of my ESP32-S3 devboard (a Heltec LoRa 32 V3).

$ espflash read-flash 0x9000 24576 config2.img
[2025-02-02T17:15:59Z INFO ] Serial port: '/dev/ttyUSB0'
[2025-02-02T17:15:59Z INFO ] Connecting...
[2025-02-02T17:15:59Z INFO ] Using flash stub
Chip type:         esp32s3 (revision v0.2)
Crystal frequency: 40 MHz
Flash size:        8MB
Features:          WiFi, BLE
MAC address:       34:cd:b0:3d:40:24
Error: espflash::read_flash::corrupt_data

  × Corrupt data, expected 1000 bytes but receved ffe bytes

Here's the full log, when running with RUST_LOG=trace: https://gist.github.com/liclac/01ee6b5f5bea1095cf37c86c43fb9f60

Doing the same operation with esptool.py works:

$ esptool.py read_flash 0x9000 24576 config.img
esptool.py v4.8.1
Found 3 serial ports
Serial port /dev/ttyUSB0
Connecting....
Detecting chip type... ESP32-S3
Chip is ESP32-S3 (QFN56) (revision v0.2)
Features: WiFi, BLE, Embedded Flash 8MB (GD)
Crystal is 40MHz
MAC: 34:cd:b0:3d:40:24
Uploading stub...
Running stub...
Stub running...
Configuring flash size...
24576 (100 %)
24576 (100 %)
Read 24576 bytes at 0x00009000 in 2.2 seconds (90.3 kbit/s)...
Hard resetting via RTS pin...

I am able to use espflash write-bin to write this dumped image back to it:

$ espflash write-bin 0x9000 config.img
[2025-02-02T17:24:06Z INFO ] Serial port: '/dev/ttyUSB0'
[2025-02-02T17:24:06Z INFO ] Connecting...
[2025-02-02T17:24:07Z INFO ] Using flash stub
Chip type:         esp32s3 (revision v0.2)
Crystal frequency: 40 MHz
Flash size:        8MB
Features:          WiFi, BLE
MAC address:       34:cd:b0:3d:40:24
[00:00:00] [========================================]       1/1       0x9000
[2025-02-02T17:24:09Z INFO ] Binary successfully written to flash!

I'm also able to change the data, write it, and read it back just fine:

$ tr \xFF \xAA < config.img > config2.img

$ espflash write-bin 0x9000 config2.img
[2025-02-02T17:26:27Z INFO ] Serial port: '/dev/ttyUSB0'
[2025-02-02T17:26:27Z INFO ] Connecting...
[2025-02-02T17:26:27Z INFO ] Using flash stub
Chip type:         esp32s3 (revision v0.2)
Crystal frequency: 40 MHz
Flash size:        8MB
Features:          WiFi, BLE
MAC address:       34:cd:b0:3d:40:24
[00:00:00] [========================================]       1/1       0x9000
[2025-02-02T17:26:29Z INFO ] Binary successfully written to flash!

$ esptool.py read_flash 0x9000 24576 config2_.img
esptool.py v4.8.1
Found 3 serial ports
Serial port /dev/ttyUSB0
Connecting....
Detecting chip type... ESP32-S3
Chip is ESP32-S3 (QFN56) (revision v0.2)
Features: WiFi, BLE, Embedded Flash 8MB (GD)
Crystal is 40MHz
MAC: 34:cd:b0:3d:40:24
Uploading stub...
Running stub...
Stub running...
Configuring flash size...
24576 (100 %)
24576 (100 %)
Read 24576 bytes at 0x00009000 in 2.2 seconds (90.3 kbit/s)...
Hard resetting via RTS pin...

$ diff <(xxd config2.img) <(xxd config2_.img)

$ $ espflash read-flash 0x9000 24576 config.img
[2025-02-02T17:31:33Z INFO ] Serial port: '/dev/ttyUSB0'
[2025-02-02T17:31:33Z INFO ] Connecting...
[2025-02-02T17:31:33Z INFO ] Using flash stub
Chip type:         esp32s3 (revision v0.2)
Crystal frequency: 40 MHz
Flash size:        8MB
Features:          WiFi, BLE
MAC address:       34:cd:b0:3d:40:24
Error: espflash::read_flash::corrupt_data

  × Corrupt data, expected 1000 bytes but receved ffd bytes

A minor observation is that for some reason, every time I re-write the partition and try reading it again, it changes how many bytes the error message says it received, just by a few bytes back or forth seemingly at random (I've seen ffc, ffd and ffe, in no particular order).

Happy to provide any additional information, help debug things, etc., but I'm a bit lost as to where to even start with this.

[liclac]

I discovered something very interesting: it seems to work fine as long as I ask for 0x1000 bytes or less. The moment I go above that, things start failing - 0x1001 through 0x1009 gets a timeout, 0x1010 and I'm back to the corruption error.

[SergioGasquez]

but I'm a bit lost as to where to even start with this.

I guess we should compare both implementations:

• esptool: https://github.com/espressif/esptool/blob/master/esptool/loader.py#L1273-L1308
• espflash: https://github.com/esp-rs/espflash/blob/main/espflash/src/flasher/mod.rs#L1106-L1185

[SergioGasquez]

I think we encountered this issue on our HIL setup:

• When using espflash read-flash 0x1000 0x200 flash_content.bin, the CI passes: https://github.com/esp-rs/espflash/actions/runs/13242998308
• When using espflash read-flash 0 0x2000 flash_content.bin, the CI fails: https://github.com/esp-rs/espflash/actions/runs/13243719658/job/36965109560

Error: espflash::read_flash::corrupt_data

  × Corrupt data, expected 1000 bytes but receved fc3 bytes

Locally, I can reproduce the issue on some devkits, but in other devkits it works fine:

• ESP8684-DevKitC-02 26MHz (clock): works fine
• ESP32-C6-DevKitC-1: Fails
• ESP32-S3-DevKitC-1: Fails