IOS10推送了已经有很长一段时间了，有觉得IOS10不够好优化太差的朋友或许可以考虑如何降级来提高流畅度，下面是IOS9的固件下载地址。

全设备iOS9下载地址：

iPhone

iPhone 4s - A1387(电信版&国际版) /A1431(联通专用型号)

http://appldnld.apple.com/ios9/058-25016-20150916-131EC4B2-5679-11E5-BBE9-BCF96CA99CB1/iPhone4,1_9.0_13A344_Restore.ipsw

iPhone 5 - A1428

http://appldnld.apple.com/ios9/058-21825-20150916-2CFEADD0-5678-11E5-9EC1-F7F76CA99CB1/iPhone5,1_9.0_13A344_Restore.ipsw

iPhone 5 - A1429/A1442(中国电信定制版)

http://appldnld.apple.com/ios9/058-23601-20150916-2D01837A-5678-11E5-97A2-F9F76CA99CB1/iPhone5,2_9.0_13A344_Restore.ipsw

iPhone 5c - A1532/A1456

http://appldnld.apple.com/ios9/058-12416-20150916-2D014842-5678-11E5-8BA0-FBF76CA99CB1/iPhone5,3_9.0_13A344_Restore.ipsw

iPhone 5c - A1516/A1526/A1529/A1507(国际版)

http://appldnld.apple.com/ios9/031-28090-20150916-2D01D21C-5678-11E5-B696-FCF76CA99CB1/iPhone5,4_9.0_13A344_Restore.ipsw

iPhone 5s - A1533/A1453

http://appldnld.apple.com/ios9/058-25026-20150916-2D01E630-5678-11E5-88C3-FEF76CA99CB1/iPhone6,1_9.0_13A344_Restore.ipsw

iPhone 5s - A1518/A1528/A1530/A1457(国际版)

http://appldnld.apple.com/ios9/058-21808-20150916-2D0C9B84-5678-11E5-A514-FFF76CA99CB1/iPhone6,2_9.0_13A344_Restore.ipsw

iPhone 6 Plus - 6 Plus(通用)

http://appldnld.apple.com/ios9/058-11566-20150916-E5FE2B8A-5678-11E5-ABA0-42F96CA99CB1/iPhone7,1_9.0_13A344_Restore.ipsw

iPhone 6 - A1586/A1549(通用)

http://appldnld.apple.com/ios9/031-29698-20150916-ECC56014-5678-11E5-9EA3-66F96CA99CB1/iPhone7,2_9.0_13A344_Restore.ipsw

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iPad

iPad 2 - A1395(WiFi版)

http://appldnld.apple.com/ios9/058-15433-20150916-2CFDDE78-5678-11E5-B33D-EDF76CA99CB1/iPad2,1_9.0_13A344_Restore.ipsw

iPad 2 - A1396(GSM 版)

http://appldnld.apple.com/ios9/058-25009-20150916-2D002BEC-5678-11E5-9B61-F1F76CA99CB1/iPad2,2_9.0_13A344_Restore.ipsw

iPad 2 - A1397(CDMA2000 版)

http://appldnld.apple.com/ios9/058-11514-20150916-2CFEFA92-5678-11E5-BF5C-F4F76CA99CB1/iPad2,3_9.0_13A344_Restore.ipsw

iPad 2 - (Rev A 新制程版)

http://appldnld.apple.com/ios9/058-21841-20150916-2CFDAEDA-5678-11E5-A181-EFF76CA99CB1/iPad2,4_9.0_13A344_Restore.ipsw

iPad 3 - A1416(WiFi版)

http://appldnld.apple.com/ios9/031-25660-20150916-2CFAB8F6-5678-11E5-80CC-D1F76CA99CB1/iPad3,1_9.0_13A344_Restore.ipsw

iPad 3 - A1403(CDMA2000 版)

http://appldnld.apple.com/ios9/058-23607-20150916-2CFB4D66-5678-11E5-BF79-D3F76CA99CB1/iPad3,2_9.0_13A344_Restore.ipsw

iPad 3 - A1430(GSM 版)

http://appldnld.apple.com/ios9/058-18866-20150916-2CFAD7A0-5678-11E5-942F-D5F76CA99CB1/iPad3,3_9.0_13A344_Restore.ipsw

iPad mini - A1432(WiFi 版)

http://appldnld.apple.com/ios9/058-26588-20150916-3C31FB08-5679-11E5-AB3F-6CFA6CA99CB1/iPad2,5_9.0_13A344_Restore.ipsw

iPad mini - A1454(GSM 版)

http://appldnld.apple.com/ios9/031-29704-20150916-5303B98E-5679-11E5-B532-D4FA6CA99CB1/iPad2,6_9.0_13A344_Restore.ipsw

iPad mini - A1455(CDMA2000 版)

http://appldnld.apple.com/ios9/058-18877-20150916-5C3330C0-5679-11E5-A105-4AFB6CA99CB1/iPad2,7_9.0_13A344_Restore.ipsw

iPad 4 - A1458(WiFi 版)

http://appldnld.apple.com/ios9/031-24741-20150916-18D8E4DC-5679-11E5-8CA2-E1F96CA99CB1/iPad3,4_9.0_13A344_Restore.ipsw

iPad 4 - A1459(GSM 版)

http://appldnld.apple.com/ios9/058-11511-20150916-1E17FD20-5679-11E5-8E15-03FA6CA99CB1/iPad3,5_9.0_13A344_Restore.ipsw

iPad 4 - A1460(CDMA2000 版)

http://appldnld.apple.com/ios9/058-11538-20150916-31C2C42C-5679-11E5-A8ED-53FA6CA99CB1/iPad3,6_9.0_13A344_Restore.ipsw

iPad mini 2 - A1489(WiFi 版)

http://appldnld.apple.com/ios9/058-18871-20150916-2CFD931E-5678-11E5-8C06-E2F76CA99CB1/iPad4,4_9.0_13A344_Restore.ipsw

iPad mini 2 - A1490(LTE 版)

http://appldnld.apple.com/ios9/031-28094-20150916-2CFDD040-5678-11E5-B196-E5F76CA99CB1/iPad4,5_9.0_13A344_Restore.ipsw

iPad mini 2 - A1491(TD-SCDMA 版)

http://appldnld.apple.com/ios9/058-12414-20150916-2CFDCA96-5678-11E5-BB80-E9F76CA99CB1/iPad4,6_9.0_13A344_Restore.ipsw

iPad Air - A1474(WiFi 版)

http://appldnld.apple.com/ios9/031-29716-20150916-2CFBDC18-5678-11E5-ADBD-D7F76CA99CB1/iPad4,1_9.0_13A344_Restore.ipsw

iPad Air - A1475(LTE 版)

http://appldnld.apple.com/ios9/058-18870-20150916-2CFAE772-5678-11E5-A803-D9F76CA99CB1/iPad4,2_9.0_13A344_Restore.ipsw

iPad Air - A1476(TD-SCDMA 版)

http://appldnld.apple.com/ios9/031-29700-20150916-2CFAB66C-5678-11E5-BBD7-DBF76CA99CB1/iPad4,3_9.0_13A344_Restore.ipsw

iPad mini 3 - A1489(WiFi 版)

http://appldnld.apple.com/ios9/058-22776-20150916-2CFC8B36-5678-11E5-BFB0-E3F76CA99CB1/iPad4,7_9.0_13A344_Restore.ipsw

iPad mini 3 - A1490(LTE 版)

http://appldnld.apple.com/ios9/058-21830-20150916-2CFF2E9A-5678-11E5-8021-E7F76CA99CB1/iPad4,8_9.0_13A344_Restore.ipsw

iPad mini 3 - A1491(TD-LTE 版)

http://appldnld.apple.com/ios9/058-23478-20150916-2CFF47FE-5678-11E5-9A20-EBF76CA99CB1/iPad4,9_9.0_13A344_Restore.ipsw

iPad Air 2 - A1566(WiFi 版)

http://appldnld.apple.com/ios9/058-11516-20150916-2CFC6282-5678-11E5-BA4A-DDF76CA99CB1/iPad5,3_9.0_13A344_Restore.ipsw

iPad Air 2 - A1567(LTE 版)

http://appldnld.apple.com/ios9/031-24750-20150916-2CFBC9DA-5678-11E5-B600-DFF76CA99CB1/iPad5,4_9.0_13A344_Restore.ipsw

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iTouch

iTouch 5 - A1421

http://appldnld.apple.com/ios9/058-21788-20150916-01FB67DA-5679-11E5-897E-8AF96CA99CB1/iPod5,1_9.0_13A344_Restore.ipsw

iTouch 6 - A1574

http://appldnld.apple.com/ios9/058-11554-20150916-2D012EAC-5678-11E5-B1A1-F5F76CA99CB1/iPod7,1_9.0_13A344_Restore.ipsw

若是觉得IOS9都无法满足自身的需要，那么恐怕是要继续降级到IOS8之类的了。