boox-attach.el

;; this function NEEDS `lexical-binding' set to `t'

(defun boox/attach-last-figure-adb (basename)
  (interactive "sName: ")
  (unless (eq major-mode 'org-mode)
    (user-error "Not in an org buffer"))
  (require 'org-attach)
  (require 'org-download)
  (let ((fp "/adb:8A3DF2BF:storage/self/primary/note/export/export.pdf"))
    (when (file-readable-p fp)
        (when-let ((tmpdir (make-temp-file "boox-export" t))
                   (tmpin (concat tmpdir "/in.pdf"))
                   (tmpout (format "%s/%s.svg" tmpdir basename)))
          (copy-file fp tmpin)
          (let ((lastpage (shell-command-to-string (format "pdfinfo %s | awk '/^Pages:/ {print $2}'" tmpin)))
                (marker (point-marker)))
            (async-start-process
             "inkscape-convert"
             "inkscape"
             (lambda (_)
               (message "Inkscape finished.")
               (with-current-buffer (marker-buffer marker)
                 (without-restriction
                   (save-excursion
                     (goto-char (marker-position marker))
                     (let ((org-attach-store-link-p 'attached))
                      (org-attach-attach tmpout nil 'cp))
                     (delete-directory tmpdir t nil)
                     (org-insert-link nil (caar org-stored-links) "")))))
             "--actions=select-by-selector:svg>g>use;delete;page-fit-to-selection"
             "--pdf-poppler"
             (concat "--pages=" lastpage)
             "-o" tmpout
             "--export-dpi=10"
             tmpin))))))

I've updated the gist to only require inkscape and insert the link asyncronously.