Can't boot Pinephone Pro into Factory Test Build for Hardware Checking

[jydoxcen]

I can't boot my newly received Pinephone Pro into the Factory Test Build for Hardware Checking linked to by the phone's wiki page. I've verified the md5 hash of the downloaded image, and tried two SD cards. The accompanying instructions on that wiki page seem to be out of date, referring to an "RE button" that is only on phones sold between January and July 2022, according to other sections of the same page. Here's the procedure I've pieced together for my phone and attempted:

1. Download file and verify md5 hash.
   
2. Gunzip it.
   
3. sudo dd if=pinephone_pro_dd_android9_QC_Test_SDboot_20220215-8GB.img of=/dev/sdb bs=1M status=progress conv=fsync
   
4. Put the SD card in the phone.
   
5. Power on / buzz once.
   
6. Hold volume down, wait for another buzz, and release.
   
7. LED changes to blue.
   
8. At this point it should boot from the SD card, but it buzzes and flashes red and yellow, and boots into the stock Manjaro with Plasma Mobile.
   

Is that image supposed to work with phones sold after July 2022?
And if so, are my above steps correct?