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| Both sides previous revision Previous revision Next revision | Previous revision Next revisionBoth sides next revision | ||
| supported_devices:432_warning [2020/08/27 18:37] – Refresh the warning and also mention 8MB difficulties hnyman | supported_devices:432_warning [2021/11/29 01:38] – [Warning about 4/32 devices] richb-hanover | ||
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| Line 1: | Line 1: | ||
| - | ====== 4/32 warning | + | ====== |
| ~~NOTOC~~ | ~~NOTOC~~ | ||
| - | |||
| - | Every operating system requires | ||
| - | - Sufficient Flash to accommodate firmware image | ||
| - | - Sufficient RAM for stable operation | ||
| <WRAP round info 100%> | <WRAP round info 100%> | ||
| - | **Devices with ≤4MB flash and/or ≤32MB RAM may still work but they will be very limited (usually they can't install or run additional packages) because they have low RAM and flash space.** Consider this when choosing a device to buy, or when deciding to flash OpenWrt on your device because it is listed as supported. | + | **TL;DR - Devices with ≤4MB flash and/or ≤32MB RAM (so-called "4/32 devices" |
| </ | </ | ||
| - | ===== Usability issues===== | + | Default builds of OpenWrt 21.02 can only run on 8/64 devices. We **recommend 16/128 devices.** Every operating system requires: |
| + | - Sufficient RAM for stable operation | ||
| + | - Sufficient Flash to accommodate the firmware image | ||
| - | **Insufficient | + | ===== Low RAM can lead to instability ===== |
| * 32 MB can barely work for minimal router/AP functions, but may repeatedly " | * 32 MB can barely work for minimal router/AP functions, but may repeatedly " | ||
| * 64 MB may still have issues with stability, depending on your hardware and use cases | * 64 MB may still have issues with stability, depending on your hardware and use cases | ||
| - | * 128 MB or more is recommended if software past basic router/AP functionality is to be used | + | * 128 MB or more is recommended |
| - | ===== Extensibility issues | + | ===== Low Flash can't load new firmware or new packages |
| - | + | ||
| - | **Barely enough Flash to accommodate OpenWrt firmware image** | + | |
| * 4MB is absolute minimum (but you won't be able to install LuCI web interface) / 8MB is barely enough (will fit LuCI and some other applications) / 16MB offers more flexibility | * 4MB is absolute minimum (but you won't be able to install LuCI web interface) / 8MB is barely enough (will fit LuCI and some other applications) / 16MB offers more flexibility | ||
| * 4MB devices can't fit anything noteworthy unless you use [[docs: | * 4MB devices can't fit anything noteworthy unless you use [[docs: | ||
| - | * If you want to be sure you can install at least a few additional software packages, | + | * 8MB (or more) of Flash lets install at least a few additional software packages, |
| + | * 16MB Flash (minimum) is recommended for the foreseeable future | ||
| Most probably, you will not be able to install the following popular packages (and others) on a device with only 4MB flash: | Most probably, you will not be able to install the following popular packages (and others) on a device with only 4MB flash: | ||
| Line 33: | Line 30: | ||
| * filesystem drivers/ | * filesystem drivers/ | ||
| - | As the current | + | As the current |
| ===== Supportability issues ===== | ===== Supportability issues ===== | ||
| - | It is getting harder or even impossible over time to support devices with low Flash + RAM. | + | It is getting harder or even impossible over time to support devices with low Flash + RAM. You will be less likely to find people willing to assist on the forums. |
| The 32 MB RAM is harder limitation than the flash size. The current Linux 5.4 barely works with a 32 MB RAM system and spikes in memory consumption can easily crash the router with OOM (Out-of-Memory) errors. | The 32 MB RAM is harder limitation than the flash size. The current Linux 5.4 barely works with a 32 MB RAM system and spikes in memory consumption can easily crash the router with OOM (Out-of-Memory) errors. | ||
| - | **OpenWrt support for those devices will end with the 19.07 release**, ie. 19.07 will be the last release with support for 4/32 MB devices. There will be no future releases and no images ready for download after 19.07. | + | **OpenWrt support for those devices will end with the 19.07 release**, ie. 19.07 will be the last release with support for 4/32 MB devices. There will be no future releases and no images ready for download after 19.07. |
| ===== Advice ===== | ===== Advice ===== | ||
| - | Users that are not expert | + | If you are not an expert |
| **16/64 as an // | **16/64 as an // | ||
| - | Users should expect that devices with less than 16 MB of flash and/or 64 MB of RAM may be unstable in basic operation under current versions of OpenWrt (17.X, 18.X). They should further | + | If a device has less than 16 MB of Flash and/ |
| + | |||
| + | Previous versions of OpenWrt (such as earlier versions of 18.06.x, 17.01.x, 15.05.x "Chaos Calmer" | ||
| + | |||
| + | |||
| + | ===== Analysis of firmware size growth ===== | ||
| + | |||
| + | As example, the size of the sysupgrade release image for WNDR3700v1, an ar71xx/ | ||
| + | |||
| + | < | ||
| + | master: | ||
| + | 21.02.0: | ||
| + | 19.07.8: | ||
| + | 18.06.8: | ||
| + | 17.01.7: | ||
| + | 15.05.1: | ||
| + | 14.07: | ||
| + | 12.09: | ||
| + | </ | ||
| - | Previous versions | + | Main reason is growth in size of the Linux kernel |
| - | ===== An analysis of the issue done by forum user slh ===== | + | ==== Longer |
| As written in [[https:// | As written in [[https:// | ||