Problem with initialisation of EG21-G

Hello everyone,
I need your help, I use a EG21-G module GSM for a project. When I try to start my module, the module reboot himself, it never finish his initialisation. I can see it in a debug terminal. In the firt time, I thought it’s my reset signal which imposes a reset on the EG21 so I shunt the reset to avoid the zero level.
Even if I did it, I continue to reset himself.
Someone have an explanation for me, or are you already have this problem with this GSM module?

Thanks for your help,


Is the power supply to the modem adequate?

Hello Snowgum,
Yes I forgot to precise that I never loose my power supply on VBAT_RF and VBAT_BB. I have a very steady voltage of 3V7.

Someone are an other possible solution because it’s a big problem for me to continue my project and to develop the soft of the GSM management?
Thanks a lot