docs(q8b): explain BIOS update via rsetup

docs/dragon/q8b/low-level-dev/spi-fw.md

@@ -12,6 +12,8 @@ BIOS 固件（BootROM + 引导程序）的核心任务是分阶段初始化硬
 
 当设备无法正常启动时，我们可以让设备进入 [EDL 模式](./edl-mode)，然后通过 EDL 工具烧录 BIOS 固件。
 
+如果系统可以正常启动，也可以通过 [Rsetup 在系统中更新 BIOS 固件](../system-config/update-bios)。本页介绍的 EDL 线刷方式不依赖系统启动，适用于系统无法启动的情况。
+
 进入 [资源汇总下载](../download) 页面，下载 `edl-ng` 压缩包并解压，然后根据自己的系统平台选择对应的版本进行 BIOS 固件的下载。
 
 ## 烧录 BIOS 固件
@@ -112,6 +114,7 @@ BIOS 固件烧录成功后，请按以下任一方式重启设备：
 
 - 重新插拔设备电源
 - 在终端执行 `edl-ng reset` 命令
+
 :::
 
 ## 擦除 BIOS 固件

docs/dragon/q8b/system-config/update-bios.md

@@ -0,0 +1,21 @@
+---
+sidebar_position: 13
+---
+
+# 在系统中更新 BIOS 固件
+
+Dragon Q8B 可以通过 Radxa OS 中的 `Rsetup` 工具更新 BIOS 固件。此方法需要系统能够正常启动并连接网络；如果系统无法启动，请使用 [EDL 线刷 BIOS 固件](../low-level-dev/spi-fw)，线刷不依赖系统启动。
+
+1. 在 Dragon Q8B 的 Radxa OS 中打开终端，运行：
+
+   ```bash
+   sudo rsetup
+   ```
+
+2. 在 `Rsetup` 中依次选择 `System` -> `Bootloader Management` -> `Update SPI Bootloader`。
+3. 选择 `radxa-dragon-q8b`，按照屏幕提示确认并等待更新完成。更新期间请保持供电稳定，不要中断操作。
+4. 更新完成后重启设备。可以参考 [查看 BIOS 版本](./check-bios-version) 确认更新结果。
+
+:::tip 找不到 Update SPI Bootloader？
+在 `Rsetup` 中选择 `System` -> `System Update`，按照提示更新系统，重启后再次打开 `Rsetup` 进行上述操作。参见 [系统更新](./system-update)。
+:::

i18n/en/docusaurus-plugin-content-docs/current/dragon/q8b/low-level-dev/spi-fw.md

@@ -12,6 +12,8 @@ The core task of BIOS firmware (BootROM + bootloader) is to initialize hardware
 
 When the device cannot boot properly, enter [EDL Mode](./edl-mode), then use the EDL tool to flash the BIOS firmware.
 
+If the system boots normally, you can also [update the BIOS firmware from the system using Rsetup](../system-config/update-bios). The EDL flashing method on this page does not depend on the OS booting, so it can be used when the system cannot start.
+
 Go to the [Resource Downloads](../download) page, download and extract the `edl-ng` archive, then select the corresponding version for your system platform to download the BIOS firmware.
 
 ## Flashing BIOS Firmware
@@ -112,6 +114,7 @@ After the BIOS firmware is successfully flashed, please restart the device using
 
 - Re-plug the device power
 - Run the `edl-ng reset` command in the terminal
+
 :::
 
 ## Erase BIOS Firmware

i18n/en/docusaurus-plugin-content-docs/current/dragon/q8b/system-config/update-bios.md

@@ -0,0 +1,21 @@
+---
+sidebar_position: 13
+---
+
+# Update BIOS Firmware from the System
+
+You can update the Dragon Q8B BIOS firmware using `Rsetup` in Radxa OS. This method requires a bootable system and a network connection. If the system cannot boot, use [EDL to flash the BIOS firmware](../low-level-dev/spi-fw); EDL flashing does not depend on the OS booting.
+
+1. Open a terminal in Radxa OS on the Dragon Q8B and run:
+
+   ```bash
+   sudo rsetup
+   ```
+
+2. In `Rsetup`, select `System` -> `Bootloader Management` -> `Update SPI Bootloader`.
+3. Select `radxa-dragon-q8b`, follow the on-screen prompts to confirm, and wait for the update to finish. Keep the power supply stable and do not interrupt the update.
+4. Restart the device when the update finishes. See [Check the BIOS Version](./check-bios-version) to verify the result.
+
+:::tip Update SPI Bootloader not shown?
+In `Rsetup`, select `System` -> `System Update` and follow the prompts to update the system. Restart, then open `Rsetup` and try again. See [System Update](./system-update).
+:::