dev builds
themes manual
device status forums
mailing lists
IRC bugs
dev guide

Search | Go
Wiki > Main > DocsIndex > FlashingRockbox (r21)

Rockbox in Flash - FAQ and User Manual

by Jörg Hohensohn aka [IDC]Dragon, JoergHohensohn
player info added by Jens Arnold aka amiconn, JensArnold


Please note that this page is no longer current, but is left here for background information. The files mentioned are no longer available. Instead Archos users should see BootBox for flashing information.

Flashing in the sense used here and elsewhere in regard to Rockbox means reprogramming the flash memory of the Archos unit.

When you bought your Archos, it came with the Archos firmware flashed. Now, you can add Rockbox to the built-in software.

Note: This page describes the flashing process in detail. If you don't want to read tons of technical mumbo jumbo, you can read the Blind man's guide to flashing Rockbox, which is a step-by-step guide to flashing Rockbox, originally intended for blind people.


  • Firmware means the flash ROM content as a whole.

  • Image means one operating software started from there.

By reprogramming the firmware, we can boot much faster. Archos has an unnecessary slow boot loader, versus the boot time for Rockbox is much faster than the disk spinup, in fact it has to wait for the disk. Your boot time will be as quick as a disk spinup (e.g. 4 seconds from powerup until resuming playback).


The replaced firmware will host a bootloader and 2 images. This is possible by compression. The first is the "permanent" backup, not to be changed any more. The second is the default one to be started, the first is only used when you hold the F1 key (all recorder models), LEFT key (Ondio) or MINUS key (player) during start. Like supplied here, the first image is the original Archos firmware, the second is empty, left for you to program and update. It can contain anything you like, if you prefer, you can program the Archos firmware to there, too.

For now, the binary contained in the brand new player flash package does contain rockbox built from current cvs in the second image slot. This is to lower the risk of flashing (at least one of the images will hopefully work) in case you don't program a second image yourself in the first step. Of course the second image can be replaced like with the other models.

Boot Loader

Original firmware


There are two programming tools supplied:

  • The first one is called "firmware_flash.rock" and is used to program the whole flash with a new content. You can also use it to revert back to the original firmware you've hopefully backup-ed. In the ideal case, you'll need this tool only once. You can view this as "formatting" the flash with the desired image structure.
  • The second one is called "rockbox_flash.rock" and is used to reprogram only the second image. It won't touch any other byte, should be safe to fool around with. If the programmed firmware is inoperational, you can still use the F1/LEFT/MINUS start with the Archos firmware and Rockbox booted from disk to try better.

The non-user tools are in the "flash" subdirectory of the cvs source files. There's an authoring tool which composed the firmware file with the bootloader and the 2 images, the bootloader project, a firmware extraction tool, the plugin sources, and the tools for the UART boot feature: a monitor program for the box and a PC tool to drive it. Feel free to review the sources for all of it, but be careful when fooling around with powerful toys!


Well, is it dangerous? Yes, certainly, like programming a mainboard BIOS, CD/DVD drive firmware, mobile phone, etc. If the power fails, your chip breaks while programming or most of all the programming software malfunctions, you'll have a dead box. We take no responsibility of any kind, you do that at your own risk. However, we tried as carefully as possible to bulletproof this code. The new firmware file is completely read before it starts programming, there are a lot of sanity checks. If any fails, it will not program. Before releasing this, we have checked the flow with exactly these files supplied here, starting from the original firmware in flash. It worked reliably, there's no reason why such low level code should behave different on your box.

The risk is slightly higher for player flashing, because (a) this is brand new and (b) it could not be tested with all hardware versions. Refer to this e-mail:

There's one ultimate safety net to bring back boxes with even completely garbled flash content: the UART boot mod, which in turn requires the serial mod. It can bring the dead back to life, with that it's possible to reflash independently from the outside, even if the flash is completely erased. It has been used that during development, else Rockbox in flash wouldn't have been possible. Extensive development effort went into the exploitation of the UART boot mod. Mechanically adept users with good soldering skills can easily perform these mods. Others may feel uncomfortable using the first tool (firmware_flash.rock) for reflashing the firmware.

To comfort you a bit again: If you are starting with a known-good image, you are unlikely to experience problems. The flash tools have been stable for quite a while. Several users have used them extensively, even flashing while playing! Although it worked, it's not the recommended method. ;-)"

About the safety of operation: Since we have dual boot, you're not giving up the Archos firmware. It's still there when you hold F1/LEFT/MINUS during startup. So even if Rockbox from flash is not 100% stable for everyone, you can still use the box, reflash the second image with an updated Rockbox copy, etc.

The flash chip being used by Archos is specified for 100,000 cycles (in words: one hundred thousand), so you don't need to worry about that wearing out.


You need two things:

  • The first is an Archos Jukebox or Ondio. All models can be flashed now (Player, Recorder, Recorder V2, FM Recorder, Ondio128 FM/SP)l. Be sure you're using the correct package, they are different!
  • Second, you need an in-circuit programmable flash. Chances are about 85% (recorders) that you have, but Archos also used an older flash chip which can't do the trick. The chance is even lower for players. To the contrary, Ondios should always be flashable, because Archos does itself provide flash updates for these. You can find out via Rockbox debug menu, entry Hardware Info. If the flash info gives you question marks (Flash M=?? D=??), you're out of luck. The only chance then is to solder in the right chip (SST39VF020?), at best with the firmware already in. If the chip is blank, you'll need the UART boot mod as well.

Flashing procedure

Short explanation: copy the firmware_*.bin files for your model from the distribution to the root directory of your box, then run the "firmware_flash.rock" plugin. Long version, step by step procedure:

  • Completely install the Rockbox version you want to have in flash, from a full .zip distribution, including all the plugins, etc.
  • Back up the current firmware, using the first option of the debug menu (Dump ROM contents). This creates 2 files in the root directory, which you may not immediately see in the Rockbox browser. The 256kB-sized "internal_rom_2000000-203FFFF.bin" one is your present firmware. Back both up to your PC. You will need them if you want to restore the flash contents.
  • download the correct package for you model, Player, Recorder (V1), FM Recorder, V2 Recorder, Ondio128 FM, Ondio SP. Copy one or two files of it to your box: firmware_*.bin (name depends on your model) into the root directory (the initial firmware for your model, with the bootloader and the Archos image). There now is also a _norom variant, copy both, the plugin will decide which one is required for your box.
  • Enter the debug menu and select the hardware info screen. Check your flash IDs (bottom line), and please make a note about your hardware mask value (recorders, Ondios; second line) or ROM version (players). The latter is just for our curiosity, not needed for the flow. If the flash info shows question marks, you can stop here, sorry.
  • Use the F2 settings (recorders) or the menu (General settings->File view->Show files) to configure seeing all files within the browser.
  • Connect the charger and make sure your batteries are also in good shape. That's just for security reasons, it's not that flashing needs more power.

  • Run the "firmware_flash.rock" plugin. It again tells you about your flash and the file it's gonna program. After F1 (recorders), LEFT (Ondio) or MENU (player) it checks the file. Your hardware mask value will be kept, it won't overwrite it. Hitting F2 (recorders), UP (Ondio) or ON (player) gives you a big warning. If we still didn't manage to scare you off, you can hit F3 (recorder), RIGHT (Ondio) or "+" (player) to actually program and verify. The programming takes just a few seconds. If the sanity check fails, you have the wrong kind of boot ROM and are out of luck by now, sorry.
  • In the unlikely event that the programming should give you any error, don't switch off the box! Otherwise you'll have seen it working for the last time. While Rockbox is still in DRAM and operational, we could upgrade the plugin via USB and try again. If you switch it off, it's gone.

Now the initial procedure is done. Since the second half of the flash is still empty, there is "just" the Archos image starting when you reboot now. Not much has changed yet. The Archos software starts a bit quicker than usual, then loads Rockbox from disk. The fun really starts when you add Rockbox to the flash, as described in the next chapter.

This is not yet true for the player, since the player binary does already contain a rockbox image in the second slot. See above why.

You may delete the ".bin" files now.

Bringing in a current or personal build of Rockbox

Short explanation: very easy, just play an .ucl file like "rockbox.ucl" from a release or build:

  • Make sure you are running the same version that you are trying to flash: play the ajbrec.ajz file.
  • Enter the .rockbox directory in the file browser (you might need to set the File View option to All Files).
  • Play the "rockbox.ucl" file (or "rombox.ucl" if you want to flash ROMBox)

Long version:

The second image is the working copy, the "rockbox_flash.rock" plugin from this package reprograms it. The plugins needs to be consistant with the Rockbox plugin API version, otherwise it will detect mismatch and won't run.

It requires an exotic input, a UCL-compressed image, because that's the internal format. UCL is a nice open-source compression library. The decompression is very fast and less than a page of C-code. The efficiency is even better than Zip with maximum compression, cooks it down to about 58% of the original size. For details on UCL, see:

Rockbox developers using Linux will have to download it from there and compile it, for Win32 and Cygwin the executables are next to the packages. The sample program from that download is called "uclpack". We'll use that to compress "rockbox.bin" which is the result of the compilation. This is a part of the build process meanwhile. If you compile Rockbox yourself, you should copy uclpack to a directory which is in the path, we recommend placing it in the same dir as SH compiler.

Don't flash any "old" builds which don't have the latest coldstart ability. They won't boot. These instructions refer to builds from cvs state 2003-07-10 on (player: 2004-12-17).

Here are the steps:

  • Normally, you'll simply download a .zip distribution. Copy all the content to the USB drive, replacing the old.
  • Force a disk boot by holding F1 (recorders), LEFT (Ondio) or MINUS (player) during power-up, or at least rolo into the new Rockbox version by "Playing" the ajbrec.ajz/ archos.mod file. This may not always be necessary, but it's better to first run the version you're about to flash. It is required if you are currently running RomBox.
  • Just "play" the .ucl file in the ".rockbox" directory, this will kick off the "rockbox_flash.rock" plugin. It's a bit similar to the other one, but it's made different to make the user aware. It will check the file, available size, etc. With F2 (recorders), UP (Ondio) or ON (player) it's being programmed, no need for warning this time. If it goes wrong, you'll still have the permanent image.
  • When done, you can restart the box and hopefully your new Rockbox image.

You may find two .ucl files in the .rockbox folder. The classical, compressed one is "rockbox.ucl". If your model has enough flash space left, there may be an additional "rombox.ucl", which is uncompressed and can run directly from flash ROM, saving some RAM. The second way is the newer and now preferred one, use this if available. See RomBox for more details.

If you like or have to, you can also flash the Archos image as the second one, e.g. in case Rockbox from flash doesn't work for you. This way you keep the dual bootloader and you can easily try different later. The .ucl of the Archos firmware is included in the package.

Restoring the original firmware

If you'd like to revert to the original firmware, you can do like you did when you flashed Rockbox for the first time. You simply use the backup files you saved when flashing Rockbox for the first time and rename "internal_rom_2000000-203FFFF.bin" to "firmware_*.bin" (name varies per model, use the filename which "firmware_flash.rock" asks for) and put it in the root.

Known issues and limitations

Rockbox has a charging screen, but it is not 100% perfect. You'll get it when the unit is off and you plug in the charger. The Rockbox charging algorithm is first measuring the battery voltage for about 40 seconds, after that it only starts charging when the capacity is below 85%. You can use the Archos charging (which always tops off) by holding F1 while plugging in. Some FM users reported charging problems even with F1, they had to revert to the original flash content. These problems should not arise for player users, because the player charging is hardware controlled.

If the plugin API is changed, new builds may render the plugins incompatible. When updating, make sure you grab those too, and RoLo or F1-boot into the new version before flashing it.

There are two variants of how the boxes starts, therefore the normal and the _norom firmware files. The vast majority of the Player/Recorder/FM/Ondio all have the same boot ROM content, differentiation comes later by flash content. Rockbox identifies this boot ROM with a CRC value of 0x222F in the hardware info screen. Some recorders have the boot ROM disabled (it might be unprogrammed) and start directly from a flash mirror at address zero. They need the new _norom firmware, it has a slightly different bootloader. Without a boot ROM there is no UART boot safety net. To compensate for that as much as possible the MiniMon monitor is included, it starts with F3+On (recorders), RIGHT+ON (Ondio) or "+"+ON (player). Using that the box can be reprogrammed via serial if the first ~2000 bytes of the flash are OK.

Download the new flash content file to your box

Depending on your model (player, recorder, FM, V2 recorder, Ondio FM/SP), download one of the 6 packages:

Movies and images

Jörg's AVI movie (1.5MB) rockbox_flash_boot.avi showing his unit booting Rockbox from flash.

Roland's screendump from the movie:


r21 - 27 Jan 2008 - 22:06:00 - MarcGuay

Parents: DocsIndex
Copyright © by the contributing authors.