修改源/etc/apt/sources.list加速

deb http://mirrors.aliyun.com/raspbian/raspbian/ buster main non-free contrib rpi firmware
deb-src http://mirrors.aliyun.com/raspbian/raspbian/ buster main non-free contrib rpi firmware

还有 /etc/apt/sources.list.d/raspi.list

deb https://mirrors.ustc.edu.cn/archive.raspberrypi.org/debian buster main

更新系统和软件包

sudo apt update
sudo apt upgrade
sudo apt install rpi-eeprom

查看更新

sudo rpi-eeprom-update

如提示

BCM2711 detected
Dedicated VL805 EEPROM detected
*** UPDATE AVAILABLE ***
BOOTLOADER: update available
CURRENT: Tue Sep 10 10:41:50 UTC 2019 (1568112110)
 LATEST: Thu Apr 16 17:11:26 UTC 2020 (1587057086)
 FW DIR: /lib/firmware/raspberrypi/bootloader/critical
VL805: up-to-date
CURRENT: 000137ad
 LATEST: 000137ad

可以执行 sudo rpi-eeprom-update -a 更新
提示如：

BCM2711 detected
Dedicated VL805 EEPROM detected
BOOTFS /boot
*** INSTALLING EEPROM UPDATES ***
BOOTLOADER: update available
CURRENT: Tue Sep 10 10:41:50 UTC 2019 (1568112110)
 LATEST: Thu Apr 16 17:11:26 UTC 2020 (1587057086)
 FW DIR: /lib/firmware/raspberrypi/bootloader/critical
VL805: up-to-date
CURRENT: 000137ad
 LATEST: 000137ad
BOOTFS /boot
EEPROM updates pending. Please reboot to apply the update.

重启即可。