diff --git a/src/lib.rs b/src/lib.rs
index 371989a7f..e230a3801 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -2444,63 +2444,93 @@ impl Build {
                     cmd.args.push("-Wl,-melf_i386".into());
                 }
 
+                //
+                // Arm Target Details
+                //
+
+                // Set Float ABI for all Arm bare-metal targets using EABIHF
                 if target.arch == "arm" && target.os == "none" && target.abi == "eabihf" {
                     cmd.args.push("-mfloat-abi=hard".into())
                 }
+                // Set -mthumb for all Thumb targets
                 if target.full_arch.starts_with("thumb") {
                     cmd.args.push("-mthumb".into());
                 }
+                // Armv6-M targets (no FPU available)
                 if target.full_arch.starts_with("thumbv6m") {
+                    // ARMv6S-M is an old name for "ARMv6-M with SVC support"
+                    // before SVC support became mandatory. Some versions of GAS care
+                    // about the difference.
                     cmd.args.push("-march=armv6s-m".into());
                 }
+                // Armv7-M targets (no FPU available)
+                if target.full_arch.starts_with("thumbv7m") {
+                    cmd.args.push("-march=armv7-m".into());
+                }
+                // Armv7E-M targets
                 if target.full_arch.starts_with("thumbv7em") {
                     cmd.args.push("-march=armv7e-m".into());
-
                     if target.abi == "eabihf" {
                         cmd.args.push("-mfpu=fpv4-sp-d16".into())
                     }
                 }
-                if target.full_arch.starts_with("thumbv7m") {
-                    cmd.args.push("-march=armv7-m".into());
-                }
+                // Armv8-M Baseline (no FPU available)
                 if target.full_arch.starts_with("thumbv8m.base") {
                     cmd.args.push("-march=armv8-m.base".into());
                 }
+                // Armv8-M Mainline targets
                 if target.full_arch.starts_with("thumbv8m.main") {
                     cmd.args.push("-march=armv8-m.main".into());
-
                     if target.abi == "eabihf" {
                         cmd.args.push("-mfpu=fpv5-sp-d16".into())
                     }
                 }
-                if target.full_arch.starts_with("armebv7r") | target.full_arch.starts_with("armv7r")
+                // ARMv6 targets
+                if target.full_arch.starts_with("armv6")
+                    || (target.full_arch.starts_with("thumbv6")
+                        && !target.full_arch.starts_with("thumbv6m"))
+                {
+                    cmd.args.push("-march=armv6".into());
+                    if target.abi == "eabihf" {
+                        // lowest common denominator FPU
+                        cmd.args.push("-mfpu=vfpv2".into());
+                    }
+                }
+                // ARMv7-R targets
+                if target.full_arch.starts_with("armebv7r")
+                    || target.full_arch.starts_with("armv7r")
+                    || target.full_arch.starts_with("thumbv7r")
                 {
                     if target.full_arch.starts_with("armeb") {
                         cmd.args.push("-mbig-endian".into());
-                    } else {
-                        cmd.args.push("-mlittle-endian".into());
                     }
-
-                    // ARM mode
-                    cmd.args.push("-marm".into());
-
-                    // R Profile
                     cmd.args.push("-march=armv7-r".into());
-
                     if target.abi == "eabihf" {
                         // lowest common denominator FPU
                         // (see Cortex-R4 technical reference manual)
                         cmd.args.push("-mfpu=vfpv3-d16".into())
                     }
                 }
-                if target.full_arch.starts_with("armv7a") {
+                // Armv7-A targets
+                if target.full_arch.starts_with("armv7a")
+                    || target.full_arch.starts_with("thumbv7a")
+                {
                     cmd.args.push("-march=armv7-a".into());
-
                     if target.abi == "eabihf" {
                         // lowest common denominator FPU
                         cmd.args.push("-mfpu=vfpv3-d16".into());
                     }
                 }
+                // Armv8-R targets
+                if target.full_arch.starts_with("armv8r")
+                    || target.full_arch.starts_with("thumbv8r")
+                {
+                    cmd.args.push("-march=armv8-r".into());
+                    if target.abi == "eabihf" {
+                        cmd.args.push("-mfpu=fp-armv8".into())
+                    }
+                }
+
                 if target.arch == "riscv32" || target.arch == "riscv64" {
                     // get the 32i/32imac/32imc/64gc/64imac/... part
                     let arch = &target.full_arch[5..];
@@ -3708,6 +3738,10 @@ impl Build {
                     "sparc64-unknown-linux-gnu" => Some("sparc64-linux-gnu"),
                     "sparc64-unknown-netbsd" => Some("sparc64--netbsd"),
                     "sparcv9-sun-solaris" => Some("sparcv9-sun-solaris"),
+                    "armv4t-none-eabi" => Some("arm-none-eabi"),
+                    "armv5te-none-eabi" => Some("arm-none-eabi"),
+                    "armv6-none-eabi" => Some("arm-none-eabi"),
+                    "armv6-none-eabihf" => Some("arm-none-eabi"),
                     "armv7a-none-eabi" => Some("arm-none-eabi"),
                     "armv7a-none-eabihf" => Some("arm-none-eabi"),
                     "armebv7r-none-eabi" => Some("arm-none-eabi"),
@@ -3715,6 +3749,9 @@ impl Build {
                     "armv7r-none-eabi" => Some("arm-none-eabi"),
                     "armv7r-none-eabihf" => Some("arm-none-eabi"),
                     "armv8r-none-eabihf" => Some("arm-none-eabi"),
+                    "thumbv4t-none-eabi" => Some("arm-none-eabi"),
+                    "thumbv5te-none-eabi" => Some("arm-none-eabi"),
+                    "thumbv6-none-eabi" => Some("arm-none-eabi"),
                     "thumbv7a-none-eabi" => Some("arm-none-eabi"),
                     "thumbv7a-none-eabihf" => Some("arm-none-eabi"),
                     "thumbv7r-none-eabi" => Some("arm-none-eabi"),