Continuous flashing red

Yes… did it as well as recreated one.

Hi @mippen,

Oh, my mistake, this video was meant to demonstrate how the core will look, sorry!


my video shows the current status on my core.
can not find any information on what only red flashing means.

Hi @mippen,

See my post above, continuous flashing red / orange like this indicates the keys on your core need to be updated. Can you follow the steps from that thread: and then email us your public key at ?


Alright… Need to figure out how the programmer shield connects…

Hi @mippen,

You can flash keys and firmware using dfu-util over USB, no programmer shield necessary! :smile:


Thanks… figured that out and have sent an email with core id + key to

1 Like

Hey @mippen , got your email and added the key, thanks! Let us know if this fixes the problem.

Thanks @jgoggins … But sadly no…
After setting the local network info the core goes to orange, and after a while back to blue flashing (no breathing).
Can not see the rainbow flashing when it waits for the name setup.

Guess I have to figure out how to jtag the device.

Hey @mippen , I’m wondering if perhaps you didn’t run this command:

dfu-util -d 1d50:607f -a 1 -s 0x00002000 -v -D core_private.der

to upload the corresponding private key matching the core_public.pem you sent me?
The logs look like this is the case.

Is the result as it should be on dfu-util -d 1d50:607f -a 1 -s 0x00002000 -v -D core_private.der ?

Copyright 2005-2008 Weston Schmidt, Harald Welte and OpenMoko Inc.
Copyright 2010-2012 Tormod Volden and Stefan Schmidt
This program is Free Software and has ABSOLUTELY NO WARRANTY
Please report bugs to

Filter on vendor = 0x1d50 product = 0x607f
Opening DFU capable USB device… ID 1d50:607f
Run-time device DFU version 011a
Found DFU: [1d50:607f] devnum=0, cfg=1, intf=0, alt=1, name="@SPI Flash : SST25x
Claiming USB DFU Interface…
Setting Alternate Setting #1
Determining device status: state = dfuERROR, status = 10
dfuERROR, clearing status
Determining device status: state = dfuIDLE, status = 0
dfuIDLE, continuing
DFU mode device DFU version 011a
Device returned transfer size 1024
No valid DFU suffix signature
Warning: File has no DFU suffix
DfuSe interface name: "SPI Flash : SST25x"
Memory segment at 0x00000000 512 x 4096 = 2097152 (rew)
Downloading to address = 0x00002000, size = 610
Poll timeout 50 ms
Download from image offset 00000000 to memory 00002000-00002261, size 610
Poll timeout 30 ms
File downloaded successfully

Managed to get it to talk to the cloud, breathing…
It also answers on Tinker app.
But when downloading a test application it goes back to the old orange problem.

Hi @mippen,

Is your test application doing anything like writing to the external flash? Is it fast flashing orange after doing an over-the-air update, or is it slowly blinking yellow?


Using the demo LED application.
The LED procedure when over-the-air update is:

Hi @mippen,

Ah darn. Thank you for posting that video! That video indicates that the external flash on your core has a bad region where the over-the-air firmware update is stored. Your core runs and downloads code, but resets into dfu mode after copying the new firmware indicating that it is faulty. Can you email us at and we can exchange that core for a working one?


This core should be under the exchange program already.
But it hearts not to get it running.

I have replaced the flash on this core.
Is there any special treatment that is needed after replacing flash?

Hi @mippen,

If you replaced the flash module, follow the steps in this post, but skip the st-link / bootloader / patch programmer stuff, just do the keys / factory reset:


The keys should be fine as the core connects to the cloud?
I replaced the firmware on both locations but it is something fishy going on.
It works fine as long as I do not download an app.

One thing I do not understand,
when doing:
write it to your OTA region and backup regions:

write it to your OTA region and backup regions:
dfu-util -d 1d50:607f -a 1 -s 0x00040000 -v -D core-firmware.bin
dfu-util -d 1d50:607f -a 1 -s 0x00060000 -v -D core-firmware.bin

read it back to disk:
dfu-util -d 1d50:607f -a 1 -s 0x00040000:68216 -v -U firmware_backup.bin
dfu-util -d 1d50:607f -a 1 -s 0x00060000:68216 -v -U firmware_ota.bin

The read files is almost blank.
Isn’t these files on both MCU and Memory?

Hi @mippen,

If you’re not able to read back from these regions, it might indicate a problem with how the flash module you replaced is connected to your core. What module did you replace it with?

Using SST25VF040B-80-4I-S2AE
Placed according to silkscreen on PCB