Over the past week, multiple users reported an issue with Wi-Fi on the Raspberry Pi 4. When using an HDMI cable with the Pi 4 at QHD resolution, Wi-Fi reportedly drops. Now, the Raspberry Pi Foundation is offering a temporary solution.
The issue is detailed in a blog post from software engineer Enrico Zini. He reproduced the issue while working at 2560 x 1440 resolution on multiple Raspberry Pi 4s and with different HDMI cables.
An electronics and software engineer, Mike Walters, on Twitter investigated the issue further. Using a HackRF, he discovered an RF noise emitting from the Pi when it's set to use QHD resolution. The RF frequency is in the same range as Wi-Fi channel 1—causing the Pi 4 to jam its own Wi-Fi.
We reached out to the Raspberry Pi Foundation for comment. The company is aware of the reports and has reproduced the issue.
"We'll look to address the issue with firmware updates starting next week. In the meantime, anyone who wants to use the 2650 x 1440 resolution and who is experiencing this issue should adjust their router to use the 2.4 GHz channel 4 or above or the 5 GHz band," a spokersperson told Tom's Hardware.
Until an official resolution makes its way to the Pi 4, Raspberry Pi users are encouraged to use this workaround.