SPI operation failed when flashing .crt being not multiple of 4

[alessio-perugini]

👋 I was trying to flash a x509 certificate bundle in a .crt format to 0x3c0000 address. Unfortunately, the tool returns the following error:

Error: × The bootloader returned an error
├─▶ Error while running FlashDeflateEnd command
╰─▶ SPI operation failed

Talking to other guys on the team we hypothesized that we could have some padding problems, so I added a few bytes at the end. Surprisingly making the .crt file multiple of 4 solved the problem, and the espflash worked perfectly!

stat -c %s google.crt

before	after
3649 Bytes	3652 Bytes

Steps to reproduce the problem

openssl s_client -showcerts -connect google.com:443 </dev/null | sed -n -e '/-.BEGIN/,/-.END/ p' > google.pem
openssl x509 -outform der -in google.pem -out google.crt
espflash write-bin -p /dev/ttyACM0 -b 921600 0x3C0000 google.crt

[2023-07-03T14:49:58Z INFO ] Serial port: '/dev/ttyACM0'
[2023-07-03T14:49:58Z INFO ] Connecting...
[2023-07-03T14:49:58Z INFO ] Using flash stub
[2023-07-03T14:49:59Z WARN ] Setting baud rate higher than 115,200 can cause issues
Chip type: esp32s3 (revision v0.1)
Crystal frequency: 40MHz
Flash size: 8MB
Features: WiFi, BLE
MAC address: dc:54:75:c3:01:18
[00:00:00] [========================================] 2/2 0x3C0000 Error: × The bootloader returned an error
├─▶ Error while running FlashDeflateEnd command
╰─▶ SPI operation failed

Steps to fix the problem

openssl s_client -showcerts -connect google.com:443 </dev/null | sed -n -e '/-.BEGIN/,/-.END/ p' > google.pem
openssl x509 -outform der -in google.pem -out google.crt
dd if=/dev/zero of=google.crt bs=1 count=1 seek=3651
espflash write-bin -p /dev/ttyACM0 -b 921600 0x3C0000 google.crt

[2023-07-03T15:01:31Z INFO ] Serial port: '/dev/ttyACM0'
[2023-07-03T15:01:31Z INFO ] Connecting...
[2023-07-03T15:01:32Z INFO ] Using flash stub
[2023-07-03T15:01:32Z WARN ] Setting baud rate higher than 115,200 can cause issues
Chip type: esp32s3 (revision v0.1)
Crystal frequency: 40MHz
Flash size: 8MB
Features: WiFi, BLE
MAC address: dc:54:75:c3:01:18
[00:00:00] [========================================] 2/2 0x3C0000

Additional information

I'm running on Ubuntu 22.04

$ uname -a
Linux ale 5.19.0-45-generic #46~22.04.1-Ubuntu SMP PREEMPT_DYNAMIC Wed Jun 7 15:06:04 UTC 20 x86_64 x86_64 x86_64 GNU/Linux

$ espflash --version
espflash 2.0.0

I was trying the flash on one the new Arduino Uno R4 WiFi (datasheet)

[SergioGasquez]

Hi! I just tried reproducing the issue and I was not able to:

❯ openssl s_client -showcerts -connect google.com:443 </dev/null | sed -n -e '/-.BEGIN/,/-.END/ p' > google.pem

depth=2 C = US, O = Google Trust Services LLC, CN = GTS Root R1
verify return:1
depth=1 C = US, O = Google Trust Services LLC, CN = GTS CA 1C3
verify return:1
depth=0 CN = *.google.com
verify return:1
DONE

❯ openssl x509 -outform der -in google.pem -out google.crt


❯ espflash write-bin -p /dev/ttyACM0 -b 921600 0x3C0000 google.crt

[2023-12-11T15:58:32Z INFO ] Serial port: '/dev/ttyACM0'
[2023-12-11T15:58:32Z INFO ] Connecting...
[2023-12-11T15:58:32Z INFO ] Using flash stub
[2023-12-11T15:58:33Z WARN ] Setting baud rate higher than 115,200 can cause issues
Chip type:         esp32s3 (revision v0.1)
Crystal frequency: 40MHz
Flash size:        8MB
Features:          WiFi, BLE
MAC address:       60:55:f9:f5:20:d4
[00:00:00] [========================================]       2/2       0x3C0000                                                                                                                                                   

❯ stat -c %s google.crt
3701

I also tried with other sizes:

❯ dd if=/dev/zero of=google.crt bs=1 count=1 seek=3748
1+0 records in
1+0 records out
1 byte copied, 1.329e-05 s, 75.2 kB/s

❯ stat -c %s google.crt
3749

❯ espflash write-bin -p /dev/ttyACM0 -b 921600 0x3C0000 google.crt

[2023-12-11T15:57:43Z INFO ] Serial port: '/dev/ttyACM0'
[2023-12-11T15:57:43Z INFO ] Connecting...
[2023-12-11T15:57:43Z INFO ] Using flash stub
[2023-12-11T15:57:44Z WARN ] Setting baud rate higher than 115,200 can cause issues
Chip type:         esp32s3 (revision v0.1)
Crystal frequency: 40MHz
Flash size:        8MB
Features:          WiFi, BLE
MAC address:       60:55:f9:f5:20:d4
[00:00:00] [========================================]       2/2       0x3C0000      

I am using espflash with that latest main changes (commit 71d7a63). We did some changes in main, could you try reproducing it with this espflash version (cargo install espflash --git https://github.com/esp-rs/espflash --force) and see if the issue still persists for you @alessio-perugini?

[alessio-perugini]

@SergioGasquez Tested on 71d7a63 now it's working flawlessly! 🚀

EDIT: I did a little bit a git bisect and found out that the first commit that fixes the problem is: 775e222