As you may have noticed, updating the firmware on the beta VESCs from VESC Tool does not work. This is because something went wrong with flashing the bootloader, so there is no bootloader present on them. I was able to come up with a hackish solution for this by making VESC Tool able to upload the bootloader using the firmware upload command with an offset. One problem with this approach is that if there already is a bootloader present that is not identical in binary (for example compiled with a different version of GCC) this can mess up the bootloader. Therefore it is important to make sure that there really is no bootloader before doing this. VESC Tool will warn about that as well. Doing this twice from the same version of VESC Tool does not cause any problem. Here are the steps to upload the bootloader and then update the firmware:
1. First make sure that the bootloader really is missing. If VESC Tool says that a firmware update is required you can update the firmware from the firmware page. If the VESC is unable to reboot by itself after this process is done and a power cycle will boot into the old firmware (meaning that VESC Tool will show the same message again) this means that the bootloader is missing. However, if the firmware is updated successfully the bootloader is working fine and you are done.
2. If the previous step shows that the bootloader is missing, go to the bootloader tab in the firmware page and upload the bootloader. After the upload is done the old firmware message is shown again, but the bootloader should be present. No reboot is required.
3. Go back to the included files tab in the firmware page and upload the latest firmware. The the VESC should reboot and the firmware should be updated and working now. The bootloader is also present, so future updates will work without the additional bootloader step.
One nice thing about this problem is that VESC Tool now is able to upload the bootloader if it is missing. I think there are many HW4.x PCBs with missing bootloaders sold, so when VESC Tool gets official people will be able to install a bootloader on them as well and use the latest firmware.