Mitel 622d not switching on blinking red

[sbg45100]

Hello,

I have several Mitel 622d not switching on, blinking red.
This is like a common pattern with this model, they used to work fine, and eventually some day they don't switch-on anymore and instead blink read when we try to switch them on.
Would anybody have an idea why ?
If this is a software issue I wish I could flash them, but I did not find any troubleshooting information on Mitel side.
Thanks ahead.
S. B.

[zoo]

Try to follow this...
https://1drv.ms/b/s!Aju8bIuuWmhWhJcg_URuL1czhXMWzQ?e=XufhPW
https://1drv.ms/u/s!Aju8bIuuWmhWhJcfykAfQ4j4jGdDLQ?e=Hr1nuJ
Booter SW might be old - but phone should boot up...
BR

[sbg45100]

Many thanks for your answer, will try it.