I have the older version of RuuviTags which does have a bit different ‘carving’ in the PCB, missing few curves.
I can successfully set the bootloader mode and connect with nRF Connect. Uploading the standard firmware package 2.5.9 fails to nRF Connect with error message “Error 6: HW version check failed”
Tried also with the older standard firmware 1.2.12
nRF Connect version is 2.3.2 build 59 on iPhone XS
I have not tried with other phones yet, thus this sounds not being an issue on that end.
You probably have a tag which is running 3.x firmware. There is a chance of bricking the tag if downgrading from 3.x to older firmwares which it is not allowed by tag.
Can you do a NFC scan of the tag to find out the current firmware version?
Hi. No luch on NFC scan. nRD Connect reports these tags to be in UART mode.
Is the firmware downgrade even possible on these? These do seem to run on the connectable mode firmware currently and I would to restore them to the stock FW to be aligned with my other tags. I did buy these second hand and did not think of such possibility that they are impossible to restore to normal FW.
Only with a SWD programmer, but the tags have same broadcast interval and data format as 2.5.9 tags by default so you should be able to use them as if they had original firmware