Updating Sync 3.4.23088 to 3.4.23188 failed and Blank Screen

Since you didn’t provide the information required by the template, this is just a guesstimation: your black screen is due to a reformat on a MY20 screen installed on a NOT-MY20 APIM.

If so, you can recover the unit by just simply installing a NOT-MY20 screen to complete the process.