已按照之前的固件编译文件指导，把ubantu升级到20.04, 下载了openmv_v4.2.1.zip并解压到ubantu目录下。在输入sudo add-apt-repository ppa:team-gcc-arm-embedded/ppa后就出现如下提示。说没有相关文件。后面尽管还能按指令输入命令，make -j$(nproc) -C src/micropython/mpy-cross好像编译成功，make -j$(nproc) TARGET=OPENMV4P -C src就编译失败。所以我想可能是之前的指令就已经错误了
root@LAPTOP-DAA71E58:/home/tomzou/work/openmv_v4.2.1# sudo add-apt-repository ppa:team-gcc-arm-embedded/ppa
This PPA is an alternative to toolchain released at https://launchpad.net/gcc-arm-embedded. The source codes for both are same. Currently supports Ubuntu 10.04/12.04/14.04/14.10 32 and 64 bit.
Detailed explanations to Launchpad PPA can be found at https://help.launchpad.net/Packaging/. That website explains how a PPA is set up and how to add existing PPA and install software from it.
Here are quick steps to install toolchain from this PPA on Ubuntu before 14.04:
Step1: Inside Ubuntu, open a terminal and input
"sudo add-apt-repository ppa:team-gcc-arm-embedded/ppa"
Step2: Continue to input
"sudo apt-get update"
Step3: Continue to input to install toolchain
"sudo apt-get install gcc-arm-embedded"
To remove installed toolchain, just input "sudo apt-get remove gnu-arm-embedded".
To update the toolchain, just repeat above step2 and step3.
If it reports error message of conflict to gcc-arm-none-eabi, which is likely if upgrading from 4.x to 5+, please uninstall it first with:
"sudo apt-get remove gcc-arm-none-eabi"
Questions should be asked at https://answers.launchpad.net/gcc-arm-embedded
Bug can be filed at https://bugs.launchpad.net/gcc-arm-embedded/+filebug. It is highly encouraged to ask question first before filing a bug.
More info: https://launchpad.net/~team-gcc-arm-embedded/+archive/ubuntu/ppa
Press [ENTER] to continue or Ctrl-c to cancel adding it.
Hit:1 http://security.ubuntu.com/ubuntu focal-security InRelease
Ign:2 http://ppa.launchpad.net/team-gcc-arm-embedded/ppa/ubuntu focal InRelease
Err:3 http://ppa.launchpad.net/team-gcc-arm-embedded/ppa/ubuntu focal Release
404 Not Found [IP: 185.125.190.52 80]
Hit:4 http://archive.ubuntu.com/ubuntu focal InRelease
Hit:5 http://archive.ubuntu.com/ubuntu focal-updates InRelease
Hit:6 http://archive.ubuntu.com/ubuntu focal-backports InRelease
Reading package lists... Done
E: The repository 'http://ppa.launchpad.net/team-gcc-arm-embedded/ppa/ubuntu focal Release' does not have a Release file.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.
root@LAPTOP-DAA71E58:/home/tomzou/work/openmv_v4.2.1#