[BL602L10] Flashing BL602L10 Cozylife Sensor: OpenBK Compatibility and Soldering Tips

Paraphrasing known movie character - Life is a box of chocolate your never know what u get. So ordering from Aliexpress couple of temperature sensors I got this surprise:




This has BL602L10 chip and unfortunately I did not find any OpenBK instructions for this device. As chip naming suggests it has only 1MB Flash. BL602L10 is L=Light, 1 = 1MB.
So I am not sure if I am able to flash it at all, however some people have managed to do this like here
https://www.elektroda.com/rtvforum/topic4039068.html
Also does OpenBK flashing software not support this chip. For this u need BLDevCube.exe from
https://github.com/bouffalolab/bl_iot_sdk (use: tools/flash_tool)

For soldering u need to get access backside of board. Soldering battery terminals will probably melt your device case so best option will be with just a little help of solder iron try prying it open just a enough to get access for wires.

[url=https://obrazki.elektroda.pl/1670641000_1729195987.jpg]

As I understand there is option to flash BL602 OTA but this is for hardcore developers with Linux available. https://www.elektroda.com/rtvforum/topic4050297.html

So far I managed to solder wires for flashing but had no success to connect it with BLDevCube. With read ID I always get error. Also I would not know what to flash to 1MB.
I will try to update this if I manage to find some relevant data.
___________________________________________________________

Update and resume about this device.

Short resume - avoid this device if possible at all cost!

Necessary pads for flash are backside of board but there is 50/50 chance to destroy the board when desoldering it from battery pads.
It is theoretically possible to flash it with BLDevCube but from 5 devices I had I was actually able to flash just one! Others just refused to connect to BLDevCube. I had to throw them away.
This device has only 1mb flash and that means if you are lucky and able to flash it you are only able to flash it UART. No OTA! (L10 means light, with 1mb)

My personal recommendation, when temperature sensor is needed, is to ditch wifi sensors completely and use Bluetooth analogs (THB2 or similar). I have not been able to achieve more than 4 months of life on any wifi temperature sensor with batteries, similar BT sensor with one battery change would last at least two years.
Unfortunately there are also door sensors and possibly some other devices with this chip, for those I don't have good alternative. In that case it is just bad luck.

a flurry of 1mb BL602L10s suddenly. I suspect I have the same device arriving today.

minusync wrote:

As I understand there is option to flash BL602 OTA but this is for hardcore developers with Linux available. https://www.elektroda.com/rtvforum/topic4050297.html

This OTA method is only for flashing Zengge/Magic Home devices.

What have you tried so far? What is BLDC erroring with? which version of BLDC are you using?

Are you pulling the DL/BOOT pin high with a 10k resistor?

There are many posts detailing how to flash BL602, but this is a good start to use as a template for any flavour BL device



Added after 3 [minutes]:

I notice this image posted is just the thumb link with no link to full size. Confirms Senyslink CHT8315 presence.



Added after 2 [minutes]:

Don't forget to take a backup of the 1mb flash when you get to that point https://www.elektroda.com/rtvforum/topic4051649.html

divadiow wrote:

There are many posts detailing how to flash BL602, but this is a good start to use as a template for any flavour BL device

I looked before I started at that video. Obviously battery powered temp sensor does not have external 12V power, so I am actually still extremely confused how to get it to boot up

divadiow wrote:

Are you pulling the DL/BOOT pin high with a 10k resistor

I combined something about 9.5K I suppose it should be close enough.

divadiow wrote:

this image posted is just the thumb

In my opinion adding images to elektroda.com is actually bad and I noticed that sometimes when I rearrange them link gets lost or nests itself in the wrong place, but yeah it should be 8315. beginning of the markings are covered with flux but numbers are seen.

minusync wrote:

I looked before I started at that video. Obviously battery powered temp sensor does not have external 12V power, so I am actually still extremely confused how to get it to boot up

no, indeed. 12v is just the supply used for the device in the video. There'll be a conversion down internally to 3.3v for the BL602.

To power your temperature sensor for flashing you should use an external 3.3v PSU. Slightly riskier is using 2 strong 1.5v batteries. I have flashed on battery before. Still, ensure your grounds are common with the USB-TTL adaptor.

Your greatest chance of success is with a decent external 3.3v power source.

Added after 3 [hours] 14 [minutes]:

Mine has arrived. Just gonna add some random pics and bits of info as I work my way with this device.


Added after 38 [minutes]:

unpaired boot log from RX-labelled test pad - 2000000 baud



Added after 54 [minutes]:

The pads on this device are labelled as to where they're to connect to, not where they're connected from on the BL602.
soldered up as follows:

RX pad -> USB-TTL RX
TX pad -> USB-TTL TX
DL pad -> 10k ohm resistor -> 3.3v PSU
VCC battery contact -> 3.3v PSU
GND battery contact -> PSU negative

USB-TTL/PSU/IoT device share common ground.



On power-up the device is in uart download mode so BL Dev Cube can be used to read flash ID, take backup and then flash firmwares.


Backup

I had to reduce read speed to 500000 because 1000000 and 2000000 were producing errors.

The backup file is attached.

After disconnecting the 10kohm resistor I paired to the Cozylife app to grab some screenshots



Then the moment of truth flashing OpenBL



flash success but it hangs on boot, perhaps not surprising given the experience of @mad_maxs in https://www.elektroda.com/rtvforum/topic4039068.html



so, investigation required. Maybe OpenBeken is simply a no-goer for 1mb BL602s given how uncommon they are.

divadiow wrote:

The pads on this device are labelled as to where they're to connect to, not where they're connected from on the BL602.

They are certainly going to great lengths to screw other people up. Now at least I get handshake success.

However I must still be doing something wrong bcs everything else is going wrong. Read ID and read flash are both basically giving this:
[18:52:15.536] - shake hand success
[18:52:15.551] - get_boot_info
[18:52:17.568] - ack is b''
[18:52:17.568] - Not ack OK
[18:52:17.568] - result:
[18:52:17.568] - fail
[18:52:17.568] - Img load fail
[18:52:17.568] - Load helper bin time cost(ms): 3629.362548828125
[18:52:17.568] - {"ErrorCode": "0003","ErrorMsg":"BFLB LOAD HELP BIN FAIL"}
[18:52:17.568] - Burn Retry
[18:52:17.568] - 0

please post some images of your whole wiring setup and the BLDevcube config

divadiow wrote:

please post some images of your whole wiring setup and the BLDevcube config

For just read ID and read flash I did not change anything from default. obviously I have com port and uart 2000000 - without that handshake would not be possible. Also I did try with 500000 read ID and read flash is still
[20:12:27.749] - shake hand success
[20:12:27.764] - get_boot_info
[20:12:29.783] - ack is b''
[20:12:29.783] - Not ack OK
[20:12:29.783] - result:
[20:12:29.783] - fail
[20:12:29.783] - Img load fail
[20:12:29.783] - Load helper bin time cost(ms): 3604.04833984375
[20:12:29.783] - {"ErrorCode": "0003","ErrorMsg":"BFLB LOAD HELP BIN FAIL"}
[20:12:29.783] - Burn Retry
[20:12:29.783] - 0
[20:12:29.783] - Burn return with retry fail

Hardware side:
RX pad -> USB-TTL RX
TX pad -> USB-TTL TX
DL pad -> 10k ohm resistor ->USB-TTL 3.3v
VCC pad -> USB-TTL 3.3v
GND pad -> USB-TTL negative

However, I noticed that u use version 1.8.9. I downloaded from github and it shows version 1.4.8. Could it be that??
I started yesterday from Buffalo Lab website but it did show me download time 3H ! From git I got all the repository zip in minute or so.

it's definitely worth a try

regarding the flash size issues and OpenBL not booting, I wonder if @p.kaczmarek2 or @insmod has any thoughts. I'm trawling the OpenBL repo for signs something should be set differently depending on the flash size. Or perhaps OBK needs to be told there's no OTA partition at x address.

Added after 8 [minutes]:



Added after 5 [minutes]:

maybe something in here? https://github.com/openshwprojects/OpenBL602/...components/hal_drv/bl602_hal/hal_boot2.c#L294

i dunno

divadiow wrote:

it's definitely worth a try

Now it actually reads ID but flash read error remains the same.
I also noticed that in "flash read jedec ID" for u it reads also mac but for me not. Obviously bcs the error it also does not show me flash size in logs.

are your cables too long? are you soldered or pogo pins? how are you powering the device?

minusync wrote:

RX pad -> USB-TTL RXTX pad -> USB-TTL TXDL pad -> 10k ohm resistor ->USB-TTL 3.3v VCC pad -> USB-TTL 3.3vGND pad -> USB-TTL negative

Just re-reading and notice you're powering from the USB-TTL. You should definitely use an external 3.3v source, especially with BL602s.

Hi all, I can verify that also while having a PSU attached while flashing the device simply will not boot.

- using dev cube 1.9.0
- was able to read ID & save original image
- flash successful

Please see images attached for my setup. Device is a Cozylife humidity sensor 602L10 based

birdman2010 wrote:

the device simply will not boot

Indeed, thanks. OpenBeken does not boot on any 1mb BL602 device to date. I do not know what needs changing in the code to fix this.

I transplanted the CHT8315 into a TH01 with CHT8310 and 2mb Beken BK7231N as this is more useful in testing than paired with a BL602L10

>>21269965

I was away, bcs I was actually already able to read the device ID when my computer crashed and after reboot I got errors "wrong line 0x0" or something similar. So I decided that in that process it destroyed my TTL board and I need a new one.
Now when I finally have 3 different boards it turns out that I am actually still unable to connect any device (also cb2s) so the only logical conclusion for me is that it must be my computer.
So from now I am not able to deal with new devices for a long time.

I am a lucky owner of a BL602L10 temp sensor. I've been doing research but I can't figure out why it doesn't boot. I suppose it's something related to the openbeken filesystem and partition table.

Having a look I could find this code that maybe we need to adapt to the 1MB partition table:

https://github.com/openshwprojects/OpenBK7231...db20682f4e6448b08d/src/littlefs/our_lfs.h#L48

I think that's just the LittleFS stuff though. I'm sure I flashed a few older BL602 releases, some way before LFS was implemented, but there was no change in boot success.

Added after 1 [minutes]:

https://github.com/openshwprojects/OpenBK7231T_App/pull/1159

could try some releases before then to be sure?

Has anybody solved flash size limit with BL602L10

Also, I could finally try again with my own device and it goes fine until I try read it.



Of course when it is not possible to flash this device some read error doesn't matter much.

I'm watching this.

1 on the watching. Unfortunately, my skills are not advanced enough to add to the discussion but very interested in the outcome after receiving four of these which I had intended to use on HA but only if I can spring from the clutches of the CozyLife app.

I have come to the conclusion that battery sensors with wifi are absolutely pointless. I threw away both of those sensors I had and will only use Bluetooth analogs (THB2 or similar) from now on. I have not been able to achieve more than 4 months of life on any wifi temperature sensor with batteries. If wifi and mqtt connection take at least 10 seconds, then BTHome connection time is in milliseconds.
None of my sensors have been used for that long, but at least theoretically, the life of such a BT sensor with one battery change would be at least two years.
Openbeken is still great for switches and other permanently powered devices but any battery devices in my opinion it is waste of time for both developers and users.

>>21417737 4 months with 2 AA batteries is just great!

>>21418209

vinibali wrote:

4 months with 2 AA batteries is just great!

This is with very big concessions. To get out 4 months, the temperature cannot be transmitted more frequently than after every 90 minutes. One of my wifi sensors that I still use, uses a scheme where if the temperature does not change much, the update does not occur until every 90 minutes. If the temperature changes quickly, the updates occur even every minute if needed.

Hello! Person that works on the Zephyr port for those chips here.

I have acquired one of those from the aliexpress 'CASECASE' store after seeing this thread (needed to confirm BL602L works as expected and also a temp sensor board is nice to add to my setup), I have successfully flashed it with Zephyr RTOS so it is something small in openbeken. I can confirm there is no efuse protection key and it should work like any other BL602 based device (very few have the lock keys) that work with openbeken beside the small memory.

My setup for flashing was:
- 18650 battery to and - where battery goes usually
- TX RX to adapter TX RX (not inverted as mentioned earlier)
- GND of adapter to GND on test points
- DL pulled high to enable flashing mode.
- used BFLB-MCU-TOOL (from pip) to flash it, but devcube worked when I backed up the flash and checked the efuses.

Just note to anybody who happens to be unfortunate to get BL602 device.
I have had 5 of those and 4 I had to throw away and I was able to flash only one device.
My advice is to avoid at any cost one of those devices