Pixl frozen in hard reset, after message "BOOTING..."

After having uploaded a big splash image with require("Storage").write(".splash",E.toArrayBuffer(atob("
my Pixl is frozen.

So I do a hard-reset, power off/on with BTN1 pressed. It starts, then displays:

DFV 2V16
RELEASE BTN1 FOR DEV
BTN1 TO BOOT

<==================================>
BOOTING...

Then the led flashes once, and the screen is frozen with the same message.

Possible reason: a JSA connector I soldered two weeks ago, but it was working OK after that.

I am happy to try to flash the memory myself.