FP4 - Stuck in fastboot mode - relock the bootloader

Hello all,
After a restless night, I read around again (here and in the Fairphone forum) and tried to determine or set the active recovery partition.

fastboot devices
811xxxxx fastboot

fastboot getvar current-slot
current-slot: b
Finished. Total time: 0.016s

fastboot --set-active=b
Setting current slot to ‘b’ OKAY [ 0.016s]
Finished. Total time: 0.016s

then I was able to start the recovery again :))

And the access via adb worked as well

So the sideload of the iodeos 3.3 with adb was possible and after some time of installation, i could start my phone inti iode again. very very happy

I didn´t wipe and erase data and didn´t reset via recovery, because i tried these steps yesterday.

And so the last question is whether it is now possible to lock the bootloader again. In some other way - or not if its to risky.

Stephan