RasPi 2: Method To Hide Freeze on "sync", Raspbian 10
Last Updated on July 7, 2020
Just check "Wait for network" in the Raspberry Pi Configuration. It seems to make the boot traditional manner rather than the fast boot. Note that I'm adding "fsck.mode=force fsck.repair=yes" in /boot/cmdline.txt. I'm also using the embedded WiFi for the online connection. I experience RasPi2 using Ethernet connection with no explicit grouding has enough stability. A radio unit makes noises to affect voltages for logics and often needs explicit grounding. Altough, I haven't probed RasPi3's logic level with the WiFi active. You can see your mobile phone has no grounding wire because you are performing as the grounding wire. Plus, your mobile phone is made of much testing and modifying not only as a radio emitter, but also as a stabilized computer. If you want to know many difficulties to make your phone, search iPhone's renewal history. The first iPhone has metal chassis which has the cellular antenna inside. The main reason of the limited number of companies to make smart phones is the big cost for development, especially testing as handy gadgets. The big cost needs the enough opportunity to collect fund from many consumers.
* However, the adavantage to have grounding is the enhancement of radio sensitivity rather than the logic stability. In my experience, when I open Chromium on grounded RasPi3, the temperature stays below the warning level whereas ungrounded one has hot. That means the radio unit gets efficient through grounding.
* "You are performing as the grounding wire", or you are another plate of a capacitor with earth's surface. Radio frequencies are so high to pass such capacitance. So, a metal plate connected with GND of the radio unit can be the substitution of you.
So, making the hidden process by "sync &" displays the next CLI line. However, the stacked "sync" process also freezes the next process you command.
Reference: HR Noise 7, How to Ground
Mutiple devices on USB sockets in booting seems to slow the process and affect auto detection of USB devices after booting. USB devices need electric power in activation and things afterwards. I only plug a keyboard and a mouse into USB sockets in booting.