我正在尝试通过命令sudo apt-get update更新Raspberry Pi 3b，但是出现了这些“哈希错误”。我已经尝试了几次此命令，但问题仍然相同。请帮助我解决此错误。这是命令运行后的输出：
sudo apt-get update
Get:1 http://raspbian.raspberrypi.org/raspbian stretch InRelease [15.0 kB]
Get:2 http://raspbian.raspberrypi.org/raspbian stretch/main armhf Packages [11.7 MB]
Err:2 http://raspbian.raspberrypi.org/raspbian stretch/main armhf Packages
Hash Sum mismatch
Hashes of expected file:
- Filesize:11662080 [weak]
- SHA256:a036d099327c871ba722cea0187061525491c81fe5aaeeb48a545e0de8b36b25
- SHA1:1ab18738896a891f6b6de1859e629abf0294deba [weak]
- MD5Sum:fc13d3b6c5064a2bfea645e80e623f2d [weak]
Hashes of received file:
- SHA256:f00a5626fd1c9e5e450705bb67773463d8c4e7bb2e015478b6366365d69b19fd
- SHA1:1ecee441f5aaa963901989fde2a20a84f55dc9c1 [weak]
- MD5Sum:773e014e13e59526b0acbedd9e843b7d [weak]
- Filesize:2985974 [weak]
Last modification reported: Sat, 13 Jul 2019 17:56:35 +0000
Release file created at: Sun, 14 Jul 2019 08:22:08 +0000
Get:3 http://raspbian.raspberrypi.org/raspbian stretch/contrib armhf Packages [56.9 kB]
Get:4 http://raspbian.raspberrypi.org/raspbian stretch/non-free armhf Packages [95.5 kB]
Get:5 http://raspbian.raspberrypi.org/raspbian stretch/rpi armhf Packages [1,360 B]
0% [Connecting to archive.raspberrypi.org (93.93.128.133)]
Hit:6 http://archive.raspberrypi.org/debian stretch InRelease
Fetched 85.1 kB in 4min 3s (349 B/s)
Reading package lists... Done
E: Failed to fetch http://raspbian.raspberrypi.org/raspbian/dists/stretch/main/binary-armhf/Packages.xz Hash Sum mismatch
Hashes of expected file:
- Filesize:11662080 [weak]
- SHA256:a036d099327c871ba722cea0187061525491c81fe5aaeeb48a545e0de8b36b25
- SHA1:1ab18738896a891f6b6de1859e629abf0294deba [weak]
- MD5Sum:fc13d3b6c5064a2bfea645e80e623f2d [weak]
Hashes of received file:
- SHA256:f00a5626fd1c9e5e450705bb67773463d8c4e7bb2e015478b6366365d69b19fd
- SHA1:1ecee441f5aaa963901989fde2a20a84f55dc9c1 [weak]
- MD5Sum:773e014e13e59526b0acbedd9e843b7d [weak]
- Filesize:2985974 [weak]
Last modification reported: Sat, 13 Jul 2019 17:56:35 +0000
Release file created at: Sun, 14 Jul 2019 08:22:08 +0000
E: Some index files failed to download. They have been ignored, or old ones used instead.***``