diff --git a/Dockerfile b/Dockerfile
index cdb01c6..d74db76 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -8,6 +8,7 @@ RUN set -eux; \
         git \
         flex \
         libgmp-dev \
+        libisl-dev \
         libmpc-dev \
         libmpfr-dev \
         texinfo \
diff --git a/README.md b/README.md
index 5d11a5b..0fad8f5 100644
--- a/README.md
+++ b/README.md
@@ -8,12 +8,12 @@ The build process works currently only on **x86-based Linux** systems. The follo
 
 * Netwide Assembler (NASM)
 * GNU Make, GNU Binutils, cmake
-* Tools and libraries to build *linux*, *binutils* and *gcc* (e.g. flex, bison, MPFR library, GMP library, MPC library)
+* Tools and libraries to build *linux*, *binutils* and *gcc* (e.g. flex, bison, MPFR library, ISL library, GMP library, MPC library)
 * Rust
 
 On Debian-based systems the packets can be installed by executing:
 ```
-  sudo apt-get install cmake nasm libmpfr-dev libmpc-dev libgmp-dev flex bison
+  sudo apt-get install cmake nasm libmpfr-dev libisl-dev libmpc-dev libgmp-dev flex bison
 ```
 
 Note: If issues arise during the build, try using requirements.sh to check the versions of the necessary packets and the configuration of the LD_LIBRARY_PATH (it should contain the MPFR library, GMP library and MPC library).
diff --git a/requirements.sh b/requirements.sh
index a58267e..8c1b445 100755
--- a/requirements.sh
+++ b/requirements.sh
@@ -1,9 +1,11 @@
 #!/bin/bash
 
-if echo "$LD_LIBRARY_PATH" | grep -q libgmp && echo "$LD_LIBRARY_PATH" | grep -q libmpc && echo "$LD_LIBRARY_PATH" | grep -q libmpfr; then
-    echo "LD_LIBRARY_PATH contains MPFR library, GMP library and MPC library"
+if echo "$LD_LIBRARY_PATH" | grep -q libgmp && echo "$LD_LIBRARY_PATH" | grep -q libisl && echo "$LD_LIBRARY_PATH" | grep -q libmpc && echo "$LD_LIBRARY_PATH" | grep -q libmpfr; then
+    echo "LD_LIBRARY_PATH contains MPFR library, ISL library, GMP library, and MPC library"
 elif ! echo "$LD_LIBRARY_PATH" | grep -q libgmp; then
     echo "LD_LIBRARY_PATH missing GMP library"
+elif ! echo "$LD_LIBRARY_PATH" | grep -q libisl; then
+    echo "LD_LIBRARY_PATH missing ISL library"
 elif ! echo "$LD_LIBRARY_PATH" | grep -q libmpc; then
     echo "LD_LIBRARY_PATH missing MPC library"
 elif ! echo "$LD_LIBRARY_PATH" | grep -q libmpfr; then
diff --git a/toolchain.sh b/toolchain.sh
index 56552aa..cd3f3e3 100755
--- a/toolchain.sh
+++ b/toolchain.sh
@@ -33,9 +33,6 @@ fi
 
 if [ ! -d "gcc" ]; then
 git clone $CLONE_DEPTH https://github.com/hermit-os/gcc.git
-wget ftp://gcc.gnu.org/pub/gcc/infrastructure/isl-0.15.tar.bz2 -O isl-0.15.tar.bz2
-tar jxf isl-0.15.tar.bz2
-mv isl-0.15 gcc/isl
 fi
 
 if [ ! -d "hermit" ]; then