diff --git a/pkgs/racket-test-core/tests/racket/read.rktl b/pkgs/racket-test-core/tests/racket/read.rktl
index ad275071cf..9fcbd401cc 100644
--- a/pkgs/racket-test-core/tests/racket/read.rktl
+++ b/pkgs/racket-test-core/tests/racket/read.rktl
@@ -1444,6 +1444,37 @@
                     (read-syntax 'm (open-input-string "#lang reader 'provides-a-reader-to-check-phase"))))])
     (anything)))
 
+
+;; ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+
+(parameterize ([read-case-sensitive #t])
+  (define (myread [in (current-input-port)])
+    (parameterize-read
+     (lambda () (read in))))
+
+  (define (parameterize-read do-read)
+    (parameterize ([current-readtable (make-a-readtable (current-readtable))])
+      (do-read)))
+  
+  (define (make-a-readtable base)
+    (make-readtable base
+                    #\! 'dispatch-macro read-directive
+                    #f  'non-terminating-macro (reparameterize-read base)))
+
+  (define (reparameterize-read base)
+    (case-lambda
+      [(c in)                  (read/recursive in c base)]
+      [(c in src line col pos) (read-syntax/recursive src in c base)]))
+  
+  (define (read-directive c in src line col pos)
+    (read-case-sensitive #f)
+    (make-special-comment #f))
+
+  ;; Parameter change takes effect for recursive read:
+  (test 'abc myread (open-input-string "#!ABC"))
+  ;; Change also sticks:
+  (test 'abc myread (open-input-string "ABC")))
+
 ;; ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 
 ;; readtable has `report-errs`:
diff --git a/racket/src/expander/read/config.rkt b/racket/src/expander/read/config.rkt
index 2184052046..f27bc055af 100644
--- a/racket/src/expander/read/config.rkt
+++ b/racket/src/expander/read/config.rkt
@@ -31,7 +31,7 @@
                       * pos
                       * indentations  ; stack of `indentation` records
                       * keep-comment? ; make main dispatch return on comment
-                      parameter-override ; mash of parameter -> value
+                      parameter-override ; hash of parameter -> value
                       parameter-cache   ; hash of parameter -> value
                       st)) ; other shared mutable state
 
@@ -99,7 +99,9 @@
                 [keep-comment? keep-comment?]
                 [st (if local-graph?
                         (read-config-state #f #f)
-                        (read-config-st config))]))
+                        (read-config-st config))]
+                [parameter-override #hasheq()]
+                [parameter-cache (make-hasheq)]))
 
 (define (port+config->srcloc in config
                              #:end-pos [given-end-pos #f])
diff --git a/racket/src/racket/src/startup.inc b/racket/src/racket/src/startup.inc
index da2b1bc3aa..62d9c77e97 100644
--- a/racket/src/racket/src/startup.inc
+++ b/racket/src/racket/src/startup.inc
@@ -52111,7 +52111,9 @@ static const char *startup_source =
 "((st63_0)"
 "(if local-graph?_0"
 "(read-config-state3.1 #f #f)"
-"(read-config-st config_0))))"
+"(read-config-st config_0)))"
+"((parameter-override64_0) '#hasheq())"
+"((parameter-cache65_0)(make-hasheq)))"
 "(read-config/inner2.1"
 " readtable61_0"
 " next-readtable62_0"
@@ -52123,8 +52125,8 @@ static const char *startup_source =
 "(read-config/inner-module-declared? the-struct_1)"
 "(read-config/inner-coerce the-struct_1)"
 "(read-config/inner-coerce-key the-struct_1)"
-"(read-config/inner-parameter-override the-struct_1)"
-"(read-config/inner-parameter-cache the-struct_1)"
+" parameter-override64_0"
+" parameter-cache65_0"
 " st63_0))"
 "                                              (raise-argument-error 'struct-copy \"read-config/inner?\" the-struct_1)))))"
 "(read-config/outer1.1"
@@ -52169,16 +52171,16 @@ static const char *startup_source =
 "(let-values(((v_0) config_0))"
 "(let-values(((the-struct_0) v_0))"
 "(if(read-config/outer? the-struct_0)"
-"(let-values(((line64_0) line_0)"
-"((col65_0) col_0)"
-"((pos66_0) pos_0)"
-"((inner67_0)(read-config/outer-inner v_0)))"
+"(let-values(((line66_0) line_0)"
+"((col67_0) col_0)"
+"((pos68_0) pos_0)"
+"((inner69_0)(read-config/outer-inner v_0)))"
 "(read-config/outer1.1"
-" inner67_0"
+" inner69_0"
 "(read-config/outer-wrap the-struct_0)"
-" line64_0"
-" col65_0"
-" pos66_0"
+" line66_0"
+" col67_0"
+" pos68_0"
 "(read-config/outer-indentations the-struct_0)"
 "(read-config/outer-keep-comment? the-struct_0)))"
 "            (raise-argument-error 'struct-copy \"read-config/outer?\" the-struct_0)))))))"
@@ -52189,10 +52191,10 @@ static const char *startup_source =
 "(let-values(((v_0) config_0))"
 "(let-values(((the-struct_0) v_0))"
 "(if(read-config/outer? the-struct_0)"
-"(let-values(((wrap68_0) #f)((inner69_0)(read-config/outer-inner v_0)))"
+"(let-values(((wrap70_0) #f)((inner71_0)(read-config/outer-inner v_0)))"
 "(read-config/outer1.1"
-" inner69_0"
-" wrap68_0"
+" inner71_0"
+" wrap70_0"
 "(read-config/outer-line the-struct_0)"
 "(read-config/outer-col the-struct_0)"
 "(read-config/outer-pos the-struct_0)"
@@ -52206,15 +52208,15 @@ static const char *startup_source =
 "(let-values(((v_0) config_0))"
 "(let-values(((the-struct_0) v_0))"
 "(if(read-config/outer? the-struct_0)"
-"(let-values(((keep-comment?70_0) #t)((inner71_0)(read-config/outer-inner v_0)))"
+"(let-values(((keep-comment?72_0) #t)((inner73_0)(read-config/outer-inner v_0)))"
 "(read-config/outer1.1"
-" inner71_0"
+" inner73_0"
 "(read-config/outer-wrap the-struct_0)"
 "(read-config/outer-line the-struct_0)"
 "(read-config/outer-col the-struct_0)"
 "(read-config/outer-pos the-struct_0)"
 "(read-config/outer-indentations the-struct_0)"
-" keep-comment?70_0))"
+" keep-comment?72_0))"
 "            (raise-argument-error 'struct-copy \"read-config/outer?\" the-struct_0)))))))"
 "(define-values"
 "(discard-comment)"
@@ -52226,15 +52228,15 @@ static const char *startup_source =
 "(let-values(((v_0) config_0))"
 "(let-values(((the-struct_0) v_0))"
 "(if(read-config/outer? the-struct_0)"
-"(let-values(((keep-comment?72_0) #f)((inner73_0)(read-config/outer-inner v_0)))"
+"(let-values(((keep-comment?74_0) #f)((inner75_0)(read-config/outer-inner v_0)))"
 "(read-config/outer1.1"
-" inner73_0"
+" inner75_0"
 "(read-config/outer-wrap the-struct_0)"
 "(read-config/outer-line the-struct_0)"
 "(read-config/outer-col the-struct_0)"
 "(read-config/outer-pos the-struct_0)"
 "(read-config/outer-indentations the-struct_0)"
-" keep-comment?72_0))"
+" keep-comment?74_0))"
 "                (raise-argument-error 'struct-copy \"read-config/outer?\" the-struct_0)))))))))"
 "(define-values"
 "(next-readtable)"
@@ -52246,12 +52248,12 @@ static const char *startup_source =
 "(let-values(((v_0) config_0))"
 "(let-values(((the-struct_0) v_0))"
 "(if(read-config/outer? the-struct_0)"
-"(let-values(((inner74_0)"
+"(let-values(((inner76_0)"
 "(let-values(((the-struct_1)(read-config/outer-inner v_0)))"
 "(if(read-config/inner? the-struct_1)"
-"(let-values(((readtable75_0)(read-config-next-readtable config_0)))"
+"(let-values(((readtable77_0)(read-config-next-readtable config_0)))"
 "(read-config/inner2.1"
-" readtable75_0"
+" readtable77_0"
 "(read-config/inner-next-readtable the-struct_1)"
 "(read-config/inner-for-syntax? the-struct_1)"
 "(read-config/inner-source the-struct_1)"
@@ -52266,7 +52268,7 @@ static const char *startup_source =
 "(read-config/inner-st the-struct_1)))"
 "                                  (raise-argument-error 'struct-copy \"read-config/inner?\" the-struct_1)))))"
 "(read-config/outer1.1"
-" inner74_0"
+" inner76_0"
 "(read-config/outer-wrap the-struct_0)"
 "(read-config/outer-line the-struct_0)"
 "(read-config/outer-col the-struct_0)"