I have unsealed succesfully to backup eeprom, then I recelled and after that voltages are read slowly and can not unseal anymore.
Communication is not stable, in this case unseal is not guaranteed.
Try to unseal with Power On option and 11000 voltage value.
@djibattworkshop I have tried with different voltages without success.
But what I did to solve this was to get the old cells (they were at 3,8 V each) that was the voltage that I could unseal before. I made all the changes in NLBA and EV2300, then I unsoldered the old cells and put the new ones. Now it seems OK, I only have to charge and discharge with suggested relax times.
What I have noticed that at present voltages it takes time to read the values. I will see how will work after calibration.