Update README

- the customizable bootargs feature was introduced in #534, but the
README was not updated at that time.

- build-linux-img should be build-linux-image. See mk/tools.mk.

- highlight WebAssembly support in feature list.

Author: ChinYikMing

README.md

@@ -26,10 +26,11 @@ Features:
 * Fast interpreter for executing the RV32 ISA
 * Fast interpreter that faithfully executes the complete RV32 instruction set
 * Full coverage of RV32I / RV32E plus the M (integer multiply–divide), A (atomics), F (single-precision floating-point), C (compressed), and Zba/Zbb/Zbc/Zbs bit-manipulation extensions
-* Built-in ELF loader for user-mode emulation
+* Built-in ELF loader for user-space emulation
 * Newlib-compatible system-call layer for standalone programs
 * Minimal system emulation capable of booting an RV32 Linux kernel and running user-space binaries
 * Experimental SDL-based display/event/audio system calls for running video games
+* WebAssembly build for user-space and system emulation with SDL graphics and audio in modern browsers
 * Remote debugging through the GDB Remote Serial Protocol
 * Tiered JIT compilation for performance boost while maintaining a small footprint
 
@@ -104,10 +105,16 @@ Mount the virtual block device and create a test file after booting, note that r
 ```
 Reboot and re-mount the virtual block device, the written file should remain existing.
 
+#### Customize bootargs
+Build and run with customized bootargs to boot the guestOS. Otherwise, the default bootargs defined in `src/devices/minimal.dts` will be used.
+```shell
+$ build/rv32emu -k <kernel_img_path> -i <rootfs_img_path> [-b <bootargs>]
+```
+
 #### Build Linux image
 An automated build script is provided to compile the RISC-V cross-compiler, Busybox, and Linux kernel from source. Please note that it only supports the Linux host environment. It can be found at tools/build-linux-image.sh.
 ```shell
-$ make build-linux-img
+$ make build-linux-image
 ```
 
 ### Verify with prebuilt RISC-V ELF files