[GH-ISSUE #58] flashing of FW Tag failes "failed to read json header from FW pack" #3337

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sascha_hemi · 2026-03-20T23:04:41+01:00

sascha_hemi commented

2026-03-20 23:04:41 +01:00

Originally created by @Uspizig on GitHub (Jun 7, 2023).
Original GitHub issue: https://github.com/OpenEPaperLink/OpenEPaperLink/issues/58

What a great project.. so far i am still having issue getting it to work.

Describe the bug
Can not flash the ZBS243 Tag. Always runs into trouble during flashing.

triple checked the wiring
checked with a mulitmeter beeper as well

To Reproduce
Steps to reproduce the behavior:

Build filesystem image
Upload filesystem Image
Build and Upload OpenEpaperLink_Mini_AP
push reset button on ESP32-s2 mini
Watch Terminal output
1. Check littleFS Filesystem in paralell on Mobilephone

`Connected! IP address: 192.168.178.35
reading DB from file
loadDB: Failed to open file
I wasn't able to connect to a ZBS (AP) tag.

This could be the first time this AP is booted and the AP-tag may be unflashed. We'll try to flash it!
If this tag was previously flashed succesfully but this message still shows up, there's probably something wrong with the serial connections.
The build of this firmware expects an AP tag with RXD/TXD on ESP32 pins 6 and 7, does this match with your wiring?
Performing firmware flash in about 30 seconds!

30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 MD5=A27D978C48888FA045E8D3F90DC27029
MD5 Matches > Segmented UK
Found an original fw tag, flashing it for use with OpenEPaperLink
Failed to read json header from FW pack
Failed to flash the AP :(
Seems like you're running into some issues with the wiring, or (very small chance) the tag itself
This ESP32-build expects the following pins connected to the ZBS243:
--- ZBS243 based tag ESP32 ---
RXD ---------------- 06
TXD ---------------- 07
CS/SS ---------------- 11
MOSI ---------------- 10
MISO ---------------- 08
CLK ---------------- 09
RSET ---------------- 13
Your firmware is configured without soft power control. This means you'll have to manually power-cycle the tag after flashing.
Please verify your wiring and try again!
---- Closed serial port COM10 due to disconnection from the machine ----`
Expected behavior
Flashing should run without issues (if MD5 Hash can be read out))
Don't get the error message json header from FW pack

Screenshots
Filesystem is there:

Originally created by @Uspizig on GitHub (Jun 7, 2023). Original GitHub issue: https://github.com/OpenEPaperLink/OpenEPaperLink/issues/58 What a great project.. so far i am still having issue getting it to work. **Describe the bug** Can not flash the ZBS243 Tag. Always runs into trouble during flashing. - triple checked the wiring - checked with a mulitmeter beeper as well **To Reproduce** Steps to reproduce the behavior: 1. Build filesystem image 2. Upload filesystem Image 3. Build and Upload OpenEpaperLink_Mini_AP 4. push reset button on ESP32-s2 mini 5. Watch Terminal output 6. 6. Check littleFS Filesystem in paralell on Mobilephone `Connected! IP address: 192.168.178.35 reading DB from file loadDB: Failed to open file I wasn't able to connect to a ZBS (AP) tag. This could be the first time this AP is booted and the AP-tag may be unflashed. We'll try to flash it! If this tag was previously flashed succesfully but this message still shows up, there's probably something wrong with the serial connections. The build of this firmware expects an AP tag with RXD/TXD on ESP32 pins 6 and 7, does this match with your wiring? Performing firmware flash in about 30 seconds! 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 **MD5=A27D978C48888FA045E8D3F90DC27029** MD5 Matches > Segmented UK **Found an original fw tag, flashing it for use with OpenEPaperLink** **Failed to read json header from FW pack** Failed to flash the AP :( Seems like you're running into some issues with the wiring, or (very small chance) the tag itself This ESP32-build expects the following pins connected to the ZBS243: --- ZBS243 based tag ESP32 --- RXD ---------------- 06 TXD ---------------- 07 CS/SS ---------------- 11 MOSI ---------------- 10 MISO ---------------- 08 CLK ---------------- 09 RSET ---------------- 13 Your firmware is configured without soft power control. This means you'll have to manually power-cycle the tag after flashing. Please verify your wiring and try again! ---- Closed serial port COM10 due to disconnection from the machine ----` **Expected behavior** Flashing should run without issues (if MD5 Hash can be read out)) Don't get the error message json header from FW pack **Screenshots** Filesystem is there: ![Screenshot_2023-06-07-21-42-27-95_40deb401b9ffe8e1df2f1cc5ba480b12](https://github.com/jjwbruijn/OpenEPaperLink/assets/56263335/3efeb1f9-0c45-41e2-9918-7bc3b3978a02) ![Screenshot_2023-06-07-21-43-36-30_40deb401b9ffe8e1df2f1cc5ba480b12](https://github.com/jjwbruijn/OpenEPaperLink/assets/56263335/e86c71f3-31a1-4a64-839f-8d186aa0f40b)

sascha_hemi added the bug label 2026-03-20 23:04:41 +01:00

sascha_hemi closed this issue

2026-03-20 23:04:41 +01:00

sascha_hemi commented

2026-03-20 23:04:42 +01:00

@atc1441 commented on GitHub (Jun 7, 2023):

Looks like you need to upload the correct "AP_FW_Pack.bin" to the ESP32.

It is only linked and if the repo is not cloned, and just downloaded via the browser, it will not replace it with the correct file.
Use this one: https://github.com/jjwbruijn/OpenEPaperLink/blob/master/binaries/AP_FW_Pack.bin

@atc1441 commented on GitHub (Jun 7, 2023): Looks like you need to upload the correct "AP_FW_Pack.bin" to the ESP32. It is only linked and if the repo is not cloned, and just downloaded via the browser, it will not replace it with the correct file. Use this one: https://github.com/jjwbruijn/OpenEPaperLink/blob/master/binaries/AP_FW_Pack.bin

sascha_hemi commented

2026-03-20 23:04:42 +01:00

@jonasniesner commented on GitHub (Jun 7, 2023):

To help us in the future, can you tell us how you downloaded the repo and what OS you where using?

@jonasniesner commented on GitHub (Jun 7, 2023): To help us in the future, can you tell us how you downloaded the repo and what OS you where using?

sascha_hemi commented

2026-03-20 23:04:42 +01:00

@atc1441 commented on GitHub (Jun 7, 2023):

A check of the size "AP_FW_Pack.bin" would help in the future,
it will only be 29 bytes big when only linked, so everything under a few Kbytes could seen as wrong so the user can be informed to download the correct one.

EDIT: the check is not really needed, since the error already tells the user something is wrong so the error message could just include more info's on what to do

I think an forced filesystem OTA update via the Browser should also download the correct one

@atc1441 commented on GitHub (Jun 7, 2023): A check of the size "AP_FW_Pack.bin" would help in the future, it will only be 29 bytes big when only linked, so everything under a few Kbytes could seen as wrong so the user can be informed to download the correct one. EDIT: the check is not really needed, since the error already tells the user something is wrong so the error message could just include more info's on what to do I think an forced filesystem OTA update via the Browser should also download the correct one

sascha_hemi commented

2026-03-20 23:04:42 +01:00

@nlimper commented on GitHub (Jun 7, 2023):

I discussed it with Jelmer already. Now we have OTA in place, we can download the AP firmware in the same way, so the fwpack will not be needed anymore in the near future.
But in the meantime, it's a good idea to change the error message a bit to make it clear what's missing. Or just place the actual file there, instead of a symlink.

@nlimper commented on GitHub (Jun 7, 2023): I discussed it with Jelmer already. Now we have OTA in place, we can download the AP firmware in the same way, so the fwpack will not be needed anymore in the near future. But in the meantime, it's a good idea to change the error message a bit to make it clear what's missing. Or just place the actual file there, instead of a symlink.

sascha_hemi commented

2026-03-20 23:04:42 +01:00

@atc1441 commented on GitHub (Jun 7, 2023):

maybe its good to have both variants, the current one in the repo as a pack like now and updates via OTA
That way it should also be ready to run even without any internet connection?!

@atc1441 commented on GitHub (Jun 7, 2023): maybe its good to have both variants, the current one in the repo as a pack like now and updates via OTA That way it should also be ready to run even without any internet connection?!

sascha_hemi commented

2026-03-20 23:04:42 +01:00

@Uspizig commented on GitHub (Jun 8, 2023):

thanks for the hints. @atc1441 pointed to the correct solution. All I had to do was replace the AP_FW_Pack.bin firmware via the browser.

Now it works like a charm.

@jonasniesner : all I did was doing a "download Zip" via the code button in this repository.
used operation system: Win 10(but shouldn't matter)

@Uspizig commented on GitHub (Jun 8, 2023): thanks for the hints. @atc1441 pointed to the correct solution. All I had to do was replace the AP_FW_Pack.bin firmware via the browser. Now it works like a charm. @jonasniesner : all I did was doing a "download Zip" via the code button in this repository. used operation system: Win 10(but shouldn't matter)

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Reference: starred/OpenEPaperLink#3337