Lilygo TTGO Lora32 ESP32 122_v07

Dear All,

I have problem for which I found no reference in the topics.
I bought a very old type of LORA capable board (which I realized very late), a Lilygo TTGO Lora32 ESP32 122_v07.
I flashed the firmwares 1.2.17, 1.2.28 and 1.2.30, all for v0.7. All work fine for the first few minutes, which is enough for pairing in BT and set the system up, but after a few minutes the board goes into a sleep mode that it never wakes up from. Going ahead of a few answers, my sleep times are set to:
Broadcasting Positio Period 600
and
Device Sleep Period 60 - 300 was also tested
I have another, newer board, which works fine.

Any answer is welcome!

Thanks,

Csasze