# CKKS Bootstrapping gives incorrect results on scale != 60?

**URL:** https://openfhe.discourse.group/t/ckks-bootstrapping-gives-incorrect-results-on-scale-60/844
**Category:** Library Questions
**Created:** [October 13, 2023, 8:54am UTC](https://openfhe.discourse.group/t/ckks-bootstrapping-gives-incorrect-results-on-scale-60/844 "2023-10-13T08:54:12Z")
**Posts on this page:** 1
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### Author: ![ypolyakov](https://yyz1.discourse-cdn.com/flex031/user_avatar/openfhe.discourse.group/ypolyakov/32/47_2.png) [@ypolyakov](https://openfhe.discourse.group/u/ypolyakov)
#### Post date: [October 13, 2023, 11:35pm UTC](https://openfhe.discourse.group/t/ckks-bootstrapping-gives-incorrect-results-on-scale-60/844/4 "2023-10-13T23:35:17Z")

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Hi @narger,

It looks like you are not using `firstMod` and `dcrtBits` correctly. The scaling factor is given by `dcrtBits`. So it should be set to 30 (note that I do not recommend setting it to lower than 40 for the scenarios with bootstrapping as the precision will be very low). `firstMod` should be \>= `dcrtBits` determines the maximum magnitude, e.g., if it is 10 bits larger, the message size can be up to 1024 or so.

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