Will my unupdated bank book affect my Non O visa renewal in Thailand?

If you don't update your passbook regularly.. then banks such as BB will make a summary entry headed CMB (which stands for 'combined') once the total number of transactions hits a certain limit.. in effect it is a net credit or debit for the period since your book was updated.. and on the surface it looks like you have lost the transaction history it relates to.. problematic if the dates happen to cover a seasoning period either before or after an extension is issued.. but you can go in to the bank can ask them to print the missing transactions that make up that CMB entry.. which you will get in statement format.. however, most banks also allow you to download a statement via your online banking.. so you could simply cover the missing entries that way.. i choose to routinely download my statements on a calendar monthly basis now.. in anticipation that they will be needed at renewal time.. and don't bother getting the CMB breakdown any more.. so probably worth checking out your online banking app to see what's available 👍

You can ask the bank to print the missed transaction

You need to check with your immigration office as policies vary but at Hua Hin office only the bank statement and a copy of the final book balance along with the certification letter matter.

I only update my bank book once a year on the day I go to get my new extension of stay. It's not a problem, the bank statements are what's important

You can ask for a 1-year transaction record to your bank branch when you apply for the next extension.

You have to show you have international transfer(s) of 65K baht every month for your next extension. Also have to show you have never dropped below 400K baht for the year after you kept 800K baht for three months to keep your current extension valid.

Both have to be shown in detailed transaction history. Lump sum record in your passbook wouldn't work.