MediaWiki API result

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            "*": "Subscribe to the mediawiki-api-announce mailing list at <https://lists.wikimedia.org/mailman/listinfo/mediawiki-api-announce> for notice of API deprecations and breaking changes."
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            "*": "Because \"rvslots\" was not specified, a legacy format has been used for the output. This format is deprecated, and in the future the new format will always be used."
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            "1914": {
                "pageid": 1914,
                "ns": 0,
                "title": "Riscv-nezha",
                "revisions": [
                    {
                        "contentformat": "text/x-wiki",
                        "contentmodel": "wikitext",
                        "*": "This page lists details about the Sipeed Nezha .\n\n== Hardware Info ==\n\n=== General ===\nAs report by [https://linux-sunxi.org/Allwinner_Nezha Linux Sunxi]\n{| class=\"wikitable\" style=\"font-weight:bold;\"\n|- style=\"font-weight:normal;\"\n! Device\n! Note\n|-\n| SOC\n| style=\"font-weight:normal;\" | Allwinner D1 @1.0Ghz\n|-\n| DRAM\n| style=\"font-weight:normal;\" | 512MiB/1GiB/2GiB DDR3 @ 792MHz, 2\u00d7<br />H5TQ4G63EFR\n|-\n| NAND\n| style=\"font-weight:normal;\" | 256MB, MX35LF2GE4AD\n|-\n| Power\n| style=\"font-weight:normal;\" | DC 5V @ 2A (via OTG or dedicated USB Type-C connector)\n|-\n| Video\n| style=\"font-weight:normal;\" | HDMI (Type A - full), LVDS\n|-\n| Audio\n| style=\"font-weight:normal;\" | 3.5mm headphone plug, HDMI, microphone array board connector, I2S\n|-\n| Network\n| style=\"font-weight:normal;\" | WiFi 802.11 b/g/n (XRadioTech XR829), 10/100/1000Mbps Ethernet (Realtek RTL8211F)\n|-\n| Storage\n| style=\"font-weight:normal;\" | \u00b5SD, SPI NAND\n|-\n| USB\n| style=\"font-weight:normal;\" | 1 USB2.0 Host, 1 USB Type-C OTG\n|-\n| Other\n| style=\"font-weight:normal;\" | Power LED, RGB LED, OK & FEL buttons\n|-\n| Headers\n| style=\"font-weight:normal;\" | 40-pin GPIO, DEBUG\n|}\n\n=== Serial Header ===\nThe Sipeed Nezha follows the Raspberry Pi line in terms of the pins for the serial header.  The serial header pins are 5V power (pin 4), ground (pin 6), TXD (pin 8), and RXD (pin 10). \n\nThe following setting can be used to connect to the Sipeed Nezha.  The serial terminal shall be enabled by default.\n\n* Speed (baud rate): 115200\n* Bits: 8\n* Parity: None\n* Stop Bits: 1\n* Flow Control: None\n\n== Software Info ==\nBy default, Nezhas ship with Debian or a Debian-like operating system called [[https://github.com/Tina-Linux/ TinaLinux]] on the SD card.  A version of the operating system also exists in the device's NAND memory.  Embedded Xinu will not overwrite the operating system in NAND, however the SD card will need to be overwritten to boot Embedded Xinu.  \n\nNezhas ship with a version of U-Boot preinstalled.  This version of U-Boot, however, does not support network booting.  We recommended network booting as it doesn't require students to write their operating system the SD cards (which can wear them out).  See [https://xinu.cs.mu.edu/index.php/Build_Backend_Pool#TFTP_Daemon here] for more information on TFTP in a Xinu lab.\n\nTo install an updated version of U-Boot on the SD card:\n\n1. Get the WIP U-Boot code for the Nezha\n\n    git clone https://github.com/smaeul/u-boot -b d1-wip\n    pushd u-boot\n\n2. Make the configuration file\n\n    make CROSS_COMPILE=riscv64-linux-gnu- nezha_defconfig\n\n3. Make U-Boot\n    \n    make CROSS_COMPILE=riscv64-linux-gnu-\n\n4. Write U-Boot to SD card.  Note, change \"x\" to the drive of the SD card.\n    sudo dd if=nboot/boot0_sdcard_sun20iw1p1.bin of=/dev/sdX bs=8192 seek=16\n    sudo dd if=nboot/boot0_sdcard_sun20iw1p1.bin of=/dev/sdX bs=8192 seek=256\n\n5. The SD card shall now have the WIP version of U-Boot.  Insert the SD-card back into the Nezha.\n\n== See also ==\n* [[WRT54G]]"
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            "1723": {
                "pageid": 1723,
                "ns": 0,
                "title": "Router Recovery",
                "revisions": [
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                        "*": "So you've created yourself an expensive paperweight...\n\nNot to worry! If you aren't breaking things, then chances are you aren't making hardcore progress. This page serves as a knowledge pool for methods to revive routers that are corrupted or otherwise considered non-functional. The information below is mostly specific to the [[WRT54GL]] as it is our most popular and well understood platform at this time. The process is somewhat similar for other models/platforms; however, some of the utilities are limited to specific platforms and commands vary slightly between bootloaders (ex. [[http://sourceforge.net/projects/u-boot/ U-Boot]] vs [[CFE]]). \n\nSometimes the router won't boot because of a corrupted NVRAM variable and a simple factory reset will resolve the problem.  Chances are if you've sought out this page you are in much deeper and probably need a more serious TFTP or [[EJTAG|JTAG]] recovery. We'll start with the simple solutions and work our way to the more intense recovery methods.\n\n== Before You Begin ==\nIf you haven't already, [[HOWTO:Backup_your_router|backup your router's configuration]]. Hopefully you did this earlier so you can restore to a \"known good\" working state. If you didn't, it is still a good idea to do that now; it can always get worse. You'll also want to grab yourself a copy of some reliable firmware. The default firmware that shipped with your router is a good place to start (generally available from the manufacturer's website). Otherwise, a stable release of your favorite embedded Linux distribution is a good alternative.\n\n== Factory Reset ==\nDon't get your hopes up for this one, but sometimes [[http://en.wikipedia.org/wiki/Occam's_razor Occam's razor]] applies to router recovery. To do a factory reset, hold down the reset switch for about 10 seconds while the unit is powered on, then unplug it.  Let it rest for a little while then power it back up.  If this isn't working for you, try the dd-wrt [[http://www.dd-wrt.com/wiki/index.php/Hard_reset_or_30/30/30 30/30/30]] reset method.\n\nThere's another option if you have access to a serial console, but your router isn't necessarily readily accessible (say locked in a rack somewhere with a pool of backends). Access the [[CFE]] as you normally would. Then, issue the command\n<code><pre>CFE> nvram erase</pre></code>\nand then reboot.  Some models do not properly reinitialize their NVRAM variables automatically, so be careful with this method. The [[WRT54GL]] does recover them conveniently from a separate stored location in flash.\n\nIf you haven't caught on by now, these methods erase any custom settings that were stored in NVRAM.  Don't forget to re-configure and commit your network settings, if applicable.\n\n== Serial Console ==\nNow is a good time to check that your serial console is up and running. If you don't see any text coming across the serial link, then you should double check your transceiver is working properly. Swap with a working one or at least try the one in question on another working router, if you have one available. If you can access the web interface (assuming the OS in flash has one) at either the default IP address or the one you configured, then your flash image is probably fine--fix your serial console. It is important that you are confident your serial console if functional; henceforth we'll be looking for output on the serial port as a metric for whether each recovery method is successful or not. \n\nIf you can see text and access the [[CFE]] but your router won't boot, try re-flashing the firmware with [[Flashing Firmware#TFTP|TFTP]]. \n\nIf you are confident the serial interface hardware is working properly but your router appears dead, then proceed to the next section.\n\n== JTAG ==\nIn a nutshell, JTAG is an external interface that allows external control of an SoC and its memory. You can read more about this on our [[EJTAG]] page. JTAG allows us to recover routers that are completely unresponsive (aka debricking). Before continuing, you'll need a JTAG cable (active or passive will do) and a header soldered to the JTAG connector on your router. See the references below for some suggestions on this bit.\n\n=== Software ===\nFor [[WRT54GL]] recovery, the popular programs are the original HairyDairyMaid utility and a port called TJTAG. If you purchase a commercial cable, it may come with a hardware specific recovery tool. This guide focuses on TJTAG. Download a copy of the source (linked below) and compile as usual. \n\nIf you built your own cable, chances are it uses a legacy printer style parallel port interface. You'll need adequate permissions to use this device in order to run the JTAG software. In *nix style systems usually means the user you execute TJTAG as must be a member of the <tt>lp</tt> group.\n\nThe result of the <tt>groups</tt> command should look something like this before you continue:\n<code><pre>\nuser@host:~$ groups\nuser lp dialout\n</pre></code>\nMembership of the <tt>dialout</tt> group isn't strictly necessary; however, you will need this as well if you want to use a local serial console.\n\n=== Establish a Connection ===\nNow we must verify that TJTAG can properly connect to the JTAG interface on the router. Connect the JTAG cable to both your PC and the router but leave the power disconnected. On most routers you will be fighting the [http://en.wikipedia.org/wiki/Watchdog_timer watchdog timer] so it is a good idea to type out whatever command you want to execute (without hitting <tt>enter</tt>), then provide power, and finally quickly hit <tt>enter</tt> as soon as the router LEDs light up. \n\n==== Active vs Passive ====\nIf you built the active buffered cable you need to add the <tt>/wiggler</tt> option to all of your TJTAG commands.  The passive unbuffered cable does not require this option and you should leave it off when using this type of cable. If you anticipate needing to revive routers often, an active cable is surely worth the additional investment in time and parts so you aren't restricted to working within 6 inches of your parallel port. Otherwise, the unbuffered cable works great provided you can manage the logistics of the restricted cable length. \n\n==== TJTAG Options ====\nThe next trick is to find the magical combination of optional TJTAG parameters which makes your router happy. Even within a single make/model this seems to vary greatly--most likely because of various flash chip manufacturers. For starters, we'll use the <tt>-probeonly</tt> option to guess and check which options will work before modifying the contents of flash. Usually something like\n<code><pre>user@host:tjtag$ ./tjtag -probeonly /wiggler /noemw /noreset</pre></code>\nwill do the trick.  If you are not getting the desired output (see below), try experimenting with the DMA, break, and reset switches. Once you've mastered the combinatorics game, you can move onto read/write operations. \n \n==== Successful Output ====\nWhen you've got the right combinations of parameters, you should see an output like this:\n<code><pre>\n==============================================\n EJTAG Debrick Utility v3.0.1 Tornado-MOD \n==============================================\n\nProbing bus ... Done\n\nInstruction Length set to 8\n\nCPU Chip ID: 00000101001101010010000101111111 (0535217F)\n*** Found a Broadcom BCM5352 Rev 1 CPU chip ***\n\n    - EJTAG IMPCODE ....... : 00000000100000000000100100000100 (00800904)\n    - EJTAG Version ....... : 1 or 2.0\n    - EJTAG DMA Support ... : Yes\n    - EJTAG Implementation flags: R4k MIPS32\n\nIssuing Processor / Peripheral Reset ... Skipped\nEnabling Memory Writes ... Skipped\nHalting Processor ... <Processor Entered Debug Mode!> ... Done\nClearing Watchdog ... Done\n\nProbing Flash at (Flash Window: 0x1fc00000) ... \nDone\n\nFlash Vendor ID: 00000000000000000000000011101100 (000000EC)\nFlash Device ID: 00000000000000000010001010100010 (000022A2)\n*** Found a K8D3216UBC  2Mx16 BotB     (4MB) Flash Chip ***\n\n    - Flash Chip Window Start .... : 1fc00000\n    - Flash Chip Window Length ... : 00400000\n    - Selected Area Start ........ : 00000000\n    - Selected Area Length ....... : 00000000\n\n\n\n *** REQUESTED OPERATION IS COMPLETE ***\n</pre></code>\nThe last line is important. Don't move on until you get this response.\n\n==== Troubleshooting ====\nIf you see something like this:\n<code><pre>\n==============================================\n EJTAG Debrick Utility v3.0.1 Tornado-MOD \n==============================================\n\nProbing bus ... Done\n\nInstruction Length set to 8\n\nCPU Chip ID: 00000101001101010010000101111111 (0535217F)\n*** Found a Broadcom BCM5352 Rev 1 CPU chip ***\n\n    - EJTAG IMPCODE ....... : 00000000100000000000100100000100 (00800904)\n    - EJTAG Version ....... : 1 or 2.0\n    - EJTAG DMA Support ... : Yes\n    - EJTAG Implementation flags: R4k MIPS32\n\nIssuing Processor / Peripheral Reset ... Done\n</pre></code>\nYou probably don't have the correct combination of options for your router.  Play with the different switches available before attempting to read/write from flash. \n\n\nIf you see something like this:\n<code><pre>\n==============================================\n EJTAG Debrick Utility v3.0.1 Tornado-MOD \n==============================================\n\nProbing bus ... Done\n\nInstruction Length set to 5\n\nCPU Chip ID: 11111111111111111111111111111111 (FFFFFFFF)\n*** Unknown or NO CPU Chip ID Detected ***\n\n*** Possible Causes:\n    1) Device is not Connected.\n    2) Device is not Powered On.\n    3) Improper JTAG Cable.\n    4) Unrecognized CPU Chip ID.\n</pre></code>\nAside from what the output mentions already check that \n* the header is soldered properly\n* tjtag has permission to use the parallel port\n* you didn't forget the <tt>/wiggler</tt> switch (active cable only).\n\n=== General Advice for Read/Write Operations ===\nIn the next few steps you'll attempt to correct some issues in flash memory that might prevent the router from booting correctly. Ideally when you deal with flash, it is best not to interrupt the process before it finishes on its own. That is why it is important to get the TJTAG options correct with the <tt>-probeonly</tt> option. If an operation hangs while attempting to read/write, don't panic.  It is probably in your best interests not to buy any lottery tickets tonight, but most likely all is not lost. Be patient--be sure you've given it ample time to complete. If it doesn't seem to be making any progress then you probably need to reset the router.  Various sources on the Internet have different opinions on the best way to reset. Nevertheless, we've found that disconnecting the power first and then canceling the operation (via CTRL+C) works the best.  Lastly, try the operation again (double check your parameters).\n\n=== Erase NVRAM ===\nStep 1. As before, it's a good idea to ensure NVRAM has been wiped out and isn't harboring corrupt variables. Use the same TJTAG options that got you a successful completion when trying to probe the device. \n\nExample:\n<code><pre>user@host:tjtag$ ./tjtag -erase:nvram /wiggler /noemw /noreset</pre></code>\nWhen the device reboots, it should reinitialize the correct NVRAM settings from the backup location within the CFE. If you now have a serial console, success, you're good to go. Don't forget to reconfigure any custom NVRAM settings. If that didn't work, read on.\n\n=== Erase the Kernel ===\nStep 2. For whatever reason, it is possible for a corrupted kernel to prevent the bootloader from producing any output. Again, use the same options you figured out during the <tt>-probeonly</tt> phase. \n\nExample:\n<code><pre>user@host:tjtag$ ./tjtag -erase:kernel /wiggler /noemw /noreset</pre></code>\nAfter rebooting your router, you should get console output that indicates the CFE was upset to find there's no kernel to load from flash.  This is normal; you did just erase this region of flash (hopefully). Now you can proceed to [[Flashing Firmware | flashing a new kernel]] or maybe you just want to [[HOWTO:Deploy_Xinu#Booting XINU on your Backend | load an elf image]] over the network.\n\nStill got a blank serial console? Read on.\n\n=== CFE Recovery ===\nStep 3. Your last ditch effort is to replace the bootloader. If your [[CFE]] is corrupted then there's no hope of booting.  Luckily, we can flash new one using TJTAG. The CFE contains a few settings unique to each router.  If you made a backup of your CFE before things went South, you can use that to restore the router to working order.  If you don't have a backup, you can borrow a copy from another identical router.  In the latter case you must customize the CFE binary a bit before using it on a different router. In the event you don't have access to a working router of the same make and model, try searching around on the Internet for a pristine CFE. There have been a few \"CFE collection\" projects out there; you might get lucky. \n\n==== Transplant Another Router's CFE ====\nIf you have the original CFE for this exact router, skip ahead to the next section. Otherwise, start by cloning the CFE of your good router using [[HOWTO:Backup_your_router|the usual methods]]. \n\nThere are a few CFE variables unique to each router.  For the WRT54GL, see our [[flash memory]] page for specific locations.  There should be a unique identifier and a pair of cryptography keys as well as the device MAC addresses. We're primarily concerned with the MAC address of the first physical Ethernet interface, but feel free to update the others as well. For the WRT54GL, 0x1E00 contains the MAC address used by the CFE at boot time. While you can override this setting later for your kernel in your local network configuration or NVRAM, you can't fool the bootloader (well you can, but not persistently). Especially, if you are running a pseudo-static DHCP configuration for a pool of backends, you'll get lots of network conflicts during the boot process unless this is set correctly. For the WRT54GL, this MAC address should match the one on the bottom sticker. Other routers have various schemes/offsets for what the address should be relative to the one printed on the case depending on how many physical interfaces the unit has and how the manufacturer chose to allocate the addresses. If you are feeling ambitious, you can update the default NVRAM settings in the CFE backup location so they are correct when you do a factory reset.  Alternatively, these can always be corrected later using the NVRAM utilities. \n\nTo edit the CFE, fire up your favorite hex editor and tweak each location as necessary. We happen to like <tt>shed</tt>, which has a nice <tt>nano</tt> like interface.  Note that with <tt>shed</tt> your changes are affecting the file directly as you make them.  There is no \"quit without saving\" option. It is always a good idea to make a copy of the CFE.BIN file you are planning to edit so you can revert to the original without having to grab it off the good router again.\n\nExample:\n<code><pre>\noffset    asc hex dec oct bin\n00001DFE:     00  000 000 00000000\n00001DFF:     00  000 000 00000000\n00001E00:  C  43  067 103 01000011\n00001E01:  0  30  048 060 00110000\n00001E02:  :  3A  058 072 00111010\n00001E03:  F  46  070 106 01000110\n00001E04:  F  46  070 106 01000110\n00001E05:  :  3A  058 072 00111010\n00001E06:  E  45  069 105 01000101\n00001E07:  E  45  069 105 01000101\n00001E08:  :  3A  058 072 00111010\n00001E09:  C  43  067 103 01000011\n00001E0A:  0  30  048 060 00110000\n00001E0B:  :  3A  058 072 00111010\n00001E0C:  F  46  070 106 01000110\n00001E0D:  F  46  070 106 01000110\n00001E0E:  :  3A  058 072 00111010\n00001E0F:  E  45  069 105 01000101\n00001E10:  E  45  069 105 01000101\n00001E11:     00  000 000 00000000\n00001E12:     FF  255 377 11111111\n00001E13:     FF  255 377 11111111\n00001E14:     FF  255 377 11111111\n                                                             1E00/40000 (hex) \nSPACE|E edit  S|W|F search  J jump to   T dec/hex   D dump     1|2|4 cursor\nX       exit  R|N   repeat  B bin edit  A ext. asc  P preview  `     endian\n</pre></code>\n\nYou should now have a CFE.BIN file with the correct MAC address(es) ready for flashing! Proceed to the instructions below as if you had a correct backup all along.\n\n==== Using the Same Router's Backup ====\nCopy your CFE binary to a file called CFE.BIN in the same directory as the TJTAG executable.  You don't have a choice for what file TJTAG reads in. When you are ready to write it to the router, once again make sure you know which TJTAG switches keep your particular router happy.\n\nExample:\n<code><pre>user@host:tjtag$ ./tjtag -flash:cfe /wiggler /noemw /noreset</pre></code>\n\nNow, go get a cup of coffee or take a power nap.  Bit-banging a few hundred kilobytes with a parallel interface can take awhile. You should see exactly what TJTAG is writing to flash whirring by as well as the percentage written slowly increasing. Sometimes the watchdog timer doesn't disable correctly and you have to try this a few times before it will keep going.  If it going to fail usually this happens within the first few seconds. \n\nA fresh CFE should fix most stubborn routers that aren't physically damaged, but we make no guarantees.  Your mileage may vary. Hopefully you have your serial console back and you can proceed to restoring a new kernel. If your router is still unresponsive, unfortunately we have no more advice for you. It is probably time to invest in a new one. \n\n== External References ==\n* [http://wiki.openwrt.org/doc/hardware/port.jtag OpenWrt JTAG Reference] (includes various DIY cable designs and links to commercial products)\n* [http://downloads.openwrt.org/utils/ OpenWrt Utilities] (HairyDairyMaid Download)\n* [http://www.tiaowiki.com/download//category.php?id=8 TJTAG Download]\n* [http://www.tiaowiki.com/w/Debrick_Routers_Using_JTAG_Cable TIAO Wiki Debrick Guide]\n* [http://sourceforge.net/projects/shed/ Shed] (Simple Hex Editor)"
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