Many hams want to upgrade the firmware of their Retevis RT90, but there are many versions of firmware on the support page of Retevis RT90. please click the picture to check.
Then, which version of firmware do you need for your Retevis RT90?
You can check your order to confirm that your Retevis RT90 is GPS or NO-GPS version. Of course, there is a GPS label on the radio if yours is GPS version.
You can check the S/N of your RT90 on the radio or the box of it. then select the right version of firmware as below.
First, please check the top four numbers. if it's before 2006, please select the Old version;
Second, if the first four number is 202006, please check the last five number. if it's from 00001 to 00197, please select the V4 version.
Third, if the first four number is 202006, and the last five number isn't from 00001 to 00197, such as 00198, 00272, and so on, please select the V5 version.
When you download and unzip the firmware file, there are both REC and CSV versions in the file.
REC: If you want to use the record function, please upgrade the REC version.
CSV: If you want to import the contact list, please upgrade the CSV version.