The $600 will be added if you WAIT for the software to be updated for the new law ---- do not be in a big hurry to file this time. It will take some time for the IRS and the programmers to get the $600 into the 2020 software. If you wait until later in February you should be able to get it all in one swoop by using the recovery rebate credit.
The stimulus check is an advance on a credit you can receive on your 2020 tax return. If something went wrong or you did not get the stimulus check this year, you can get it when you file your 2020 return in early 2021—if you are eligible.It will end up on line 30 of your 2020 Form 1040.
https://www.irs.gov/newsroom/economic-impact-payment-information-center-topic-j-reconciling-on-your-...
https://www.irs.gov/coronavirus/coronavirus-tax-relief-and-economic-impact-payments-for-individuals-...
https://ttlc.intuit.com/community/tax-topics/help/how-will-the-stimulus-package-impact-me/00/1393859
At this point, we do not know yet what the new stimulus bill will mean in terms of changes to the 2020 Form 1040, software programming, software updates, etc., etc. Do NOT be in a hurry to file your 2020 tax return until more is known. It is never a good idea to file early, and it would be especially foolish to file an early 2020 return.
