diff --git a/racket/src/bc/src/startup.inc b/racket/src/bc/src/startup.inc
index 048907fab9..db5c456c55 100644
--- a/racket/src/bc/src/startup.inc
+++ b/racket/src/bc/src/startup.inc
@@ -314,19 +314,62 @@ static const char *startup_source =
 "          (let-values () (raise-argument-error 'normal-path-case \"(or/c path-for-some-system? path-string?)\" s_0)))"
 "(if(if(path-for-some-system? s_0)(eq?(path-convention-type s_0) 'windows)(eq?(system-type) 'windows))"
 "(let-values()"
-"(let-values(((str_0)(if(string? s_0) s_0(bytes->string/locale(path->bytes s_0)))))"
-"              (if (regexp-match? '#rx\"^[\\\\][\\\\][?][\\\\]\" str_0)"
-"(if(string? s_0)(string->path s_0) s_0)"
-"(let-values(((s_1)(string-locale-downcase str_0)))"
-"(bytes->path"
-"(string->bytes/locale"
-"(regexp-replace*"
-"                     '#rx\"/\""
-"                     (if (regexp-match? '#rx\"[/\\\\][. ]+[/\\\\]*$\" s_1)"
+"(let-values(((bstr_0)(if(string? s_0) #f(path->bytes s_0))))"
+"              (if (if (string? s_0) (regexp-match? '#rx\"^[\\\\][\\\\][?][\\\\]\" s_0) #f)"
+"(let-values()(string->path s_0))"
+"                (if (if bstr_0 (regexp-match? '#rx#\"^[\\\\][\\\\][?][\\\\]\" bstr_0) #f)"
+"(let-values() s_0)"
+"(let-values()"
+"(let-values(((norm_0)"
+"(lambda(s_1)"
+"                                    (begin 'norm (string-locale-downcase (regexp-replace* '#rx\"/\" s_1 bsbs)))))"
+"((norm-tail_0)"
+"(lambda(s_1)"
+"(begin"
+" 'norm-tail"
+"                                      (if (regexp-match? '#rx\"[/\\\\][. ]+[/\\\\]*$\" s_1)"
 " s_1"
-"                       (regexp-replace* '#rx\"[ .]+([/\\\\]*)$\" s_1 \"\\\\1\"))"
-" bsbs))"
-" 'windows)))))"
+"                                        (regexp-replace* '#rx\"(?<=[^ ./\\\\])[ .]+([/\\\\]*)$\" s_1 \"\\\\1\")))))"
+"((finish_0)(lambda(bstr_1)(begin 'finish(bytes->path bstr_1 'windows)))))"
+"(if(string? s_0)"
+"(let-values()(finish_0(string->bytes/locale(norm_0(norm-tail_0 s_0)))))"
+"(let-values()"
+"                          (let-values (((c_0) (bytes-open-converter \"\" \"UTF-8\")))"
+"(finish_0"
+"((letrec-values(((loop_0)"
+"(lambda(offset_0)"
+"(begin"
+" 'loop"
+"(let-values(((new-bstr_0 used_0 status_0)"
+"(bytes-convert"
+" c_0"
+" bstr_0"
+" offset_0"
+"(bytes-length bstr_0))))"
+"(let-values(((s_1)(bytes->string/locale new-bstr_0)))"
+"(let-values(((tail-s_0)"
+"(if(eq? status_0 'complete)"
+"(norm-tail_0 s_1)"
+" s_1)))"
+"(let-values(((done_0)"
+"(string->bytes/locale(norm_0 tail-s_0))))"
+"(if(eq? status_0 'complete)"
+"(let-values() done_0)"
+"(if(eq? status_0 'aborts)"
+"(let-values()"
+"(bytes-append"
+" done_0"
+"(subbytes bstr_0(+ offset_0 used_0))))"
+"(let-values()"
+"(bytes-append"
+" done_0"
+"(subbytes"
+" bstr_0"
+"(+ offset_0 used_0)"
+"(+ offset_0 used_0 1))"
+"(loop_0(+ offset_0 used_0 1))))))))))))))"
+" loop_0)"
+" 0)))))))))))"
 "(if(string? s_0)(let-values()(string->path s_0))(let-values() s_0)))))))"
 "(define-values"
 "(check-extension-call)"
@@ -1919,17 +1962,17 @@ static const char *startup_source =
 "        (let-values () (raise-argument-error 'in-hash-values \"hash?\" ht_0))))))"
 "(define-values"
 "(check-ranges)"
-"(lambda(who_0 vec_0 start_0 stop_0 step_0 len_0)"
+"(lambda(who_0 type-name_0 vec_0 start_0 stop_0 step_0 len_0)"
 "(begin"
 "(begin"
 "(if(if(exact-nonnegative-integer? start_0)"
 "(let-values(((or-part_0)(< start_0 len_0)))(if or-part_0 or-part_0(= len_0 start_0 stop_0)))"
 " #f)"
 "(void)"
-"          (let-values () (raise-range-error who_0 \"vector\" \"starting \" start_0 vec_0 0 (sub1 len_0))))"
+"          (let-values () (raise-range-error who_0 type-name_0 \"starting \" start_0 vec_0 0 (sub1 len_0))))"
 "(if(if(exact-integer? stop_0)(if(<= -1 stop_0)(<= stop_0 len_0) #f) #f)"
 "(void)"
-"          (let-values () (raise-range-error who_0 \"vector\" \"stopping \" stop_0 vec_0 -1 len_0)))"
+"          (let-values () (raise-range-error who_0 type-name_0 \"stopping \" stop_0 vec_0 -1 len_0)))"
 "(if(if(exact-integer? step_0)(not(zero? step_0)) #f)"
 "(void)"
 "          (let-values () (raise-argument-error who_0 \"(and/c exact-integer? (not/c zero?))\" step_0)))"
@@ -1965,7 +2008,18 @@ static const char *startup_source =
 "(if(vector?_0 vec_0)(void)(let-values()(raise-argument-error who_0 type-name_0 vec_0)))"
 "(let-values(((len_0)(unsafe-vector-length_0 vec_0)))"
 "(let-values(((stop*_0)(if stop_0 stop_0 len_0)))"
-"(begin(check-ranges who_0 vec_0 start_0 stop*_0 step_0 len_0)(values vec_0 start_0 stop*_0 step_0))))))))"
+"(begin"
+"(check-ranges who_0 type-name_0 vec_0 start_0 stop*_0 step_0 len_0)"
+"(values vec_0 start_0 stop*_0 step_0))))))))"
+"(define-values"
+"(unsafe-normalise-inputs)"
+"(lambda(unsafe-vector-length_0 vec_0 start_0 stop_0 step_0)"
+"(begin"
+"(values"
+" vec_0"
+" start_0"
+"(let-values(((or-part_0) stop_0))(if or-part_0 or-part_0(unsafe-vector-length_0 vec_0)))"
+" step_0))))"
 "(define-values"
 "(check-vector)"
 "  (lambda (v_0) (begin (if (vector? v_0) (void) (let-values () (raise-argument-error 'in-vector \"vector\" v_0))))))"
@@ -5472,15 +5526,23 @@ static const char *startup_source =
 " key_0"
 "(reverse$1"
 "(let-values(((v*_0 start*_0 stop*_0 step*_0)"
+"(if(variable-reference-from-unsafe?"
+"(#%variable-reference))"
+"(unsafe-normalise-inputs"
+" unsafe-vector-length"
+"(struct->vector s_1)"
+" 1"
+" #f"
+" 1)"
 "(normalise-inputs"
 " 'in-vector"
-"                                                                 \"vector\""
+"                                                                   \"vector\""
 "(lambda(x_0)(vector? x_0))"
 "(lambda(x_0)(unsafe-vector-length x_0))"
 "(struct->vector s_1)"
 " 1"
 " #f"
-" 1)))"
+" 1))))"
 "(begin"
 " #t"
 "((letrec-values(((for-loop_0)"
@@ -18863,9 +18925,18 @@ static const char *startup_source =
 " start*_0"
 " stop*_0"
 " step*_0)"
+"(if(variable-reference-from-unsafe?"
+"(#%variable-reference))"
+"(unsafe-normalise-inputs"
+" unsafe-vector-length"
+"(struct->vector"
+" v_1)"
+" 1"
+" #f"
+" 1)"
 "(normalise-inputs"
 " 'in-vector"
-"                                                                                                            \"vector\""
+"                                                                                                              \"vector\""
 "(lambda(x_0)"
 "(vector?"
 " x_0))"
@@ -18876,7 +18947,7 @@ static const char *startup_source =
 " v_1)"
 " 1"
 " #f"
-" 1)))"
+" 1))))"
 "(begin"
 " #t"
 "((letrec-values(((for-loop_0)"
@@ -19510,9 +19581,17 @@ static const char *startup_source =
 " start*_0"
 " stop*_0"
 " step*_0)"
+"(if(variable-reference-from-unsafe?"
+"(#%variable-reference))"
+"(unsafe-normalise-inputs"
+" unsafe-vector-length"
+" vec_0"
+" 1"
+" #f"
+" 1)"
 "(normalise-inputs"
 " 'in-vector"
-"                                                                                                                                                          \"vector\""
+"                                                                                                                                                            \"vector\""
 "(lambda(x_0)"
 "(vector?"
 " x_0))"
@@ -19522,7 +19601,7 @@ static const char *startup_source =
 " vec_0"
 " 1"
 " #f"
-" 1)))"
+" 1))))"
 "(begin"
 " #t"
 "((letrec-values(((for-loop_0)"
@@ -21670,9 +21749,18 @@ static const char *startup_source =
 " start*_0"
 " stop*_0"
 " step*_0)"
+"(if(variable-reference-from-unsafe?"
+"(#%variable-reference))"
+"(unsafe-normalise-inputs"
+" unsafe-vector-length"
+"(struct->vector"
+" v_2)"
+" 1"
+" #f"
+" 1)"
 "(normalise-inputs"
 " 'in-vector"
-"                                                                                                                                     \"vector\""
+"                                                                                                                                       \"vector\""
 "(lambda(x_0)"
 "(vector?"
 " x_0))"
@@ -21683,7 +21771,7 @@ static const char *startup_source =
 " v_2)"
 " 1"
 " #f"
-" 1)))"
+" 1))))"
 "(begin"
 " #t"
 "((letrec-values(((for-loop_0)"
@@ -21731,9 +21819,18 @@ static const char *startup_source =
 " start*_0"
 " stop*_0"
 " step*_0)"
+"(if(variable-reference-from-unsafe?"
+"(#%variable-reference))"
+"(unsafe-normalise-inputs"
+" unsafe-vector-length"
+"(struct->vector"
+" v_2)"
+" 1"
+" #f"
+" 1)"
 "(normalise-inputs"
 " 'in-vector"
-"                                                                                                                                           \"vector\""
+"                                                                                                                                             \"vector\""
 "(lambda(x_0)"
 "(vector?"
 " x_0))"
@@ -21744,7 +21841,7 @@ static const char *startup_source =
 " v_2)"
 " 1"
 " #f"
-" 1)))"
+" 1))))"
 "(begin"
 " #t"
 "((letrec-values(((for-loop_0)"
@@ -22445,9 +22542,17 @@ static const char *startup_source =
 " start*_0"
 " stop*_0"
 " step*_0)"
+"(if(variable-reference-from-unsafe?"
+"(#%variable-reference))"
+"(unsafe-normalise-inputs"
+" unsafe-vector-length"
+" vec_0"
+" 1"
+" #f"
+" 1)"
 "(normalise-inputs"
 " 'in-vector"
-"                                                                                                                                   \"vector\""
+"                                                                                                                                     \"vector\""
 "(lambda(x_0)"
 "(vector?"
 " x_0))"
@@ -22457,7 +22562,7 @@ static const char *startup_source =
 " vec_0"
 " 1"
 " #f"
-" 1)))"
+" 1))))"
 "(begin"
 " #t"
 "((letrec-values(((for-loop_0)"
@@ -24110,15 +24215,24 @@ static const char *startup_source =
 "(let-values()"
 "(begin"
 "(let-values(((v*_0 start*_0 stop*_0 step*_0)"
-"(normalise-inputs"
-" 'in-vector"
-"                                                                               \"vector\""
-"(lambda(x_0)(vector? x_0))"
-"(lambda(x_0)(unsafe-vector-length x_0))"
+"(if(variable-reference-from-unsafe?"
+"(#%variable-reference))"
+"(unsafe-normalise-inputs"
+" unsafe-vector-length"
 "(struct->vector v_1)"
 " 1"
 " #f"
-" 1)))"
+" 1)"
+"(normalise-inputs"
+" 'in-vector"
+"                                                                                 \"vector\""
+"(lambda(x_0)(vector? x_0))"
+"(lambda(x_0)"
+"(unsafe-vector-length x_0))"
+"(struct->vector v_1)"
+" 1"
+" #f"
+" 1))))"
 "(begin"
 " #t"
 "((letrec-values(((for-loop_0)"
@@ -30792,8 +30906,8 @@ static const char *startup_source =
 "(list* 'vector-cas! syntax-literals-id '(pos #f stx))"
 "(list*"
 " 'let-values"
-"(list(list '(stx)(list* 'unsafe-vector*-ref syntax-literals-id '(pos))))"
-" '((if stx stx(loop))))))))"
+"(list(list '(new-stx)(list* 'unsafe-vector*-ref syntax-literals-id '(pos))))"
+" '((if new-stx new-stx(loop))))))))"
 " '((loop))))))))))))))))))))"
 "(define-values"
 "(generate-lazy-syntax-literals-data!)"